# Theory NSCA

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theory NSCA
imports NSComplex
begin

    (*  Title       : NSCA.thy
        Author      : Jacques D. Fleuriot
        Copyright   : 2001,2002 University of Edinburgh
    *)

    header{*Non-Standard Complex Analysis*}

    theory NSCA
    imports NSComplex
    begin

    constdefs

       CInfinitesimal  :: "hcomplex set"
       "CInfinitesimal == {x. ∀r ∈ Reals. 0 < r --> hcmod x < r}"

        capprox    :: "[hcomplex,hcomplex] => bool"  (infixl "@c=" 50)
          --{*the ``infinitely close'' relation*}
          "x @c= y == (x - y) ∈ CInfinitesimal"

       (* standard complex numbers reagarded as an embedded subset of NS complex *)
       SComplex  :: "hcomplex set"
       "SComplex == {x. ∃r. x = hcomplex_of_complex r}"

       CFinite :: "hcomplex set"
       "CFinite == {x. ∃r ∈ Reals. hcmod x < r}"

       CInfinite :: "hcomplex set"
       "CInfinite == {x. ∀r ∈ Reals. r < hcmod x}"

       stc :: "hcomplex => hcomplex"
        --{* standard part map*}
       "stc x == (@r. x ∈ CFinite & r:SComplex & r @c= x)"

       cmonad    :: "hcomplex => hcomplex set"
       "cmonad x  == {y. x @c= y}"

       cgalaxy   :: "hcomplex => hcomplex set"
       "cgalaxy x == {y. (x - y) ∈ CFinite}"

    subsection{*Closure Laws for SComplex, the Standard Complex Numbers*}

    lemma SComplex_add: "[| x ∈ SComplex; y ∈ SComplex |] ==> x + y ∈ SComplex"
    apply (simp add: SComplex_def, safe)
    apply (rule_tac x = "r + ra" in exI, simp)
    done

    lemma SComplex_mult: "[| x ∈ SComplex; y ∈ SComplex |] ==> x * y ∈ SComplex"
    apply (simp add: SComplex_def, safe)
    apply (rule_tac x = "r * ra" in exI, simp)
    done

    lemma SComplex_inverse: "x ∈ SComplex ==> inverse x ∈ SComplex"
    apply (simp add: SComplex_def)
    apply (blast intro: star_of_inverse [symmetric])
    done

    lemma SComplex_divide: "[| x ∈ SComplex;  y ∈ SComplex |] ==> x/y ∈ SComplex"
    by (simp add: SComplex_mult SComplex_inverse divide_inverse)

    lemma SComplex_minus: "x ∈ SComplex ==> -x ∈ SComplex"
    apply (simp add: SComplex_def)
    apply (blast intro: star_of_minus [symmetric])
    done

    lemma SComplex_minus_iff [simp]: "(-x ∈ SComplex) = (x ∈ SComplex)"
    apply auto
    apply (erule_tac [2] SComplex_minus)
    apply (drule SComplex_minus, auto)
    done

    lemma SComplex_diff: "[| x ∈ SComplex; y ∈ SComplex |] ==> x - y ∈ SComplex"
    by (simp add: diff_minus SComplex_add)

    lemma SComplex_add_cancel:
         "[| x + y ∈ SComplex; y ∈ SComplex |] ==> x ∈ SComplex"
    by (drule SComplex_diff, assumption, simp)

    lemma SReal_hcmod_hcomplex_of_complex [simp]:
         "hcmod (hcomplex_of_complex r) ∈ Reals"
    by (auto simp add: hcmod SReal_def star_of_def)

    lemma SReal_hcmod_number_of [simp]: "hcmod (number_of w ::hcomplex) ∈ Reals"
    apply (subst star_of_number_of [symmetric])
    apply (rule SReal_hcmod_hcomplex_of_complex)
    done

    lemma SReal_hcmod_SComplex: "x ∈ SComplex ==> hcmod x ∈ Reals"
    by (auto simp add: SComplex_def)

    lemma SComplex_hcomplex_of_complex [simp]: "hcomplex_of_complex x ∈ SComplex"
    by (simp add: SComplex_def)

    lemma SComplex_number_of [simp]: "(number_of w ::hcomplex) ∈ SComplex"
    apply (subst star_of_number_of [symmetric])
    apply (rule SComplex_hcomplex_of_complex)
    done

    lemma SComplex_divide_number_of:
         "r ∈ SComplex ==> r/(number_of w::hcomplex) ∈ SComplex"
    apply (simp only: divide_inverse)
    apply (blast intro!: SComplex_number_of SComplex_mult SComplex_inverse)
    done

    lemma SComplex_UNIV_complex:
         "{x. hcomplex_of_complex x ∈ SComplex} = (UNIV::complex set)"
    by (simp add: SComplex_def)

    lemma SComplex_iff: "(x ∈ SComplex) = (∃y. x = hcomplex_of_complex y)"
    by (simp add: SComplex_def)

    lemma hcomplex_of_complex_image:
         "hcomplex_of_complex `(UNIV::complex set) = SComplex"
    by (auto simp add: SComplex_def)

    lemma inv_hcomplex_of_complex_image: "inv hcomplex_of_complex `SComplex = UNIV"
    apply (auto simp add: SComplex_def)
    apply (rule inj_hcomplex_of_complex [THEN inv_f_f, THEN subst], blast)
    done

    lemma SComplex_hcomplex_of_complex_image:
          "[| ∃x. x: P; P ≤ SComplex |] ==> ∃Q. P = hcomplex_of_complex ` Q"
    apply (simp add: SComplex_def, blast)
    done

    lemma SComplex_SReal_dense:
         "[| x ∈ SComplex; y ∈ SComplex; hcmod x < hcmod y
          |] ==> ∃r ∈ Reals. hcmod x< r & r < hcmod y"
    apply (auto intro: SReal_dense simp add: SReal_hcmod_SComplex)
    done

    lemma SComplex_hcmod_SReal:
          "z ∈ SComplex ==> hcmod z ∈ Reals"
    by (auto simp add: SComplex_def SReal_def hcmod_def)

    lemma SComplex_zero [simp]: "0 ∈ SComplex"
    by (simp add: SComplex_def)

    lemma SComplex_one [simp]: "1 ∈ SComplex"
    by (simp add: SComplex_def)

    (*
    Goalw [SComplex_def,SReal_def] "hcmod z ∈ Reals ==> z ∈ SComplex"
    by (res_inst_tac [("z","z")] eq_Abs_hcomplex 1);
    by (auto_tac (claset(),simpset() addsimps [hcmod,hypreal_of_real_def,
        hcomplex_of_complex_def,cmod_def]));
    *)

    subsection{*The Finite Elements form a Subring*}

    lemma CFinite_add: "[|x ∈ CFinite; y ∈ CFinite|] ==> (x+y) ∈ CFinite"
    apply (simp add: CFinite_def)
    apply (blast intro!: SReal_add hcmod_add_less)
    done

    lemma CFinite_mult: "[|x ∈ CFinite; y ∈ CFinite|] ==> x*y ∈ CFinite"
    apply (simp add: CFinite_def)
    apply (blast intro!: SReal_mult hcmod_mult_less)
    done

    lemma CFinite_minus_iff [simp]: "(-x ∈ CFinite) = (x ∈ CFinite)"
    by (simp add: CFinite_def)

    lemma SComplex_subset_CFinite [simp]: "SComplex ≤ CFinite"
    apply (auto simp add: SComplex_def CFinite_def)
    apply (rule_tac x = "1 + hcmod (hcomplex_of_complex r) " in bexI)
    apply (auto intro: SReal_add)
    done

    lemma HFinite_hcmod_hcomplex_of_complex [simp]:
         "hcmod (hcomplex_of_complex r) ∈ HFinite"
    by (auto intro!: SReal_subset_HFinite [THEN subsetD])

    lemma CFinite_hcomplex_of_complex [simp]: "hcomplex_of_complex x ∈ CFinite"
    by (auto intro!: SComplex_subset_CFinite [THEN subsetD])

    lemma CFiniteD: "x ∈ CFinite ==> ∃t ∈ Reals. hcmod x < t"
    by (simp add: CFinite_def)

    lemma CFinite_hcmod_iff: "(x ∈ CFinite) = (hcmod x ∈ HFinite)"
    by (simp add: CFinite_def HFinite_def)

    lemma CFinite_number_of [simp]: "number_of w ∈ CFinite"
    by (rule SComplex_number_of [THEN SComplex_subset_CFinite [THEN subsetD]])

    lemma CFinite_bounded: "[|x ∈ CFinite; y ≤ hcmod x; 0 ≤ y |] ==> y: HFinite"
    by (auto intro: HFinite_bounded simp add: CFinite_hcmod_iff)

    subsection{*The Complex Infinitesimals form a Subring*}

    lemma CInfinitesimal_zero [iff]: "0 ∈ CInfinitesimal"
    by (simp add: CInfinitesimal_def)

    lemma hcomplex_sum_of_halves: "x/(2::hcomplex) + x/(2::hcomplex) = x"
    by auto

    lemma CInfinitesimal_hcmod_iff:
       "(z ∈ CInfinitesimal) = (hcmod z ∈ Infinitesimal)"
    by (simp add: CInfinitesimal_def Infinitesimal_def)

    lemma one_not_CInfinitesimal [simp]: "1 ∉ CInfinitesimal"
    by (simp add: CInfinitesimal_hcmod_iff)

    lemma CInfinitesimal_add:
         "[| x ∈ CInfinitesimal; y ∈ CInfinitesimal |] ==> (x+y) ∈ CInfinitesimal"
    apply (auto simp add: CInfinitesimal_hcmod_iff)
    apply (rule hrabs_le_Infinitesimal)
    apply (rule_tac y = "hcmod y" in Infinitesimal_add, auto)
    done

    lemma CInfinitesimal_minus_iff [simp]:
         "(-x:CInfinitesimal) = (x:CInfinitesimal)"
    by (simp add: CInfinitesimal_def)

    lemma CInfinitesimal_diff:
         "[| x ∈ CInfinitesimal;  y ∈ CInfinitesimal |] ==> x-y ∈ CInfinitesimal"
    by (simp add: diff_minus CInfinitesimal_add)

    lemma CInfinitesimal_mult:
         "[| x ∈ CInfinitesimal; y ∈ CInfinitesimal |] ==> x * y ∈ CInfinitesimal"
    by (auto intro: Infinitesimal_mult simp add: CInfinitesimal_hcmod_iff hcmod_mult)

    lemma CInfinitesimal_CFinite_mult:
         "[| x ∈ CInfinitesimal; y ∈ CFinite |] ==> (x * y) ∈ CInfinitesimal"
    by (auto intro: Infinitesimal_HFinite_mult simp add: CInfinitesimal_hcmod_iff CFinite_hcmod_iff hcmod_mult)

    lemma CInfinitesimal_CFinite_mult2:
         "[| x ∈ CInfinitesimal; y ∈ CFinite |] ==> (y * x) ∈ CInfinitesimal"
    by (auto dest: CInfinitesimal_CFinite_mult simp add: mult_commute)

    lemma CInfinite_hcmod_iff: "(z ∈ CInfinite) = (hcmod z ∈ HInfinite)"
    by (simp add: CInfinite_def HInfinite_def)

    lemma CInfinite_inverse_CInfinitesimal:
         "x ∈ CInfinite ==> inverse x ∈ CInfinitesimal"
    by (auto intro: HInfinite_inverse_Infinitesimal simp add: CInfinitesimal_hcmod_iff CInfinite_hcmod_iff hcmod_hcomplex_inverse)

    lemma CInfinite_mult: "[|x ∈ CInfinite; y ∈ CInfinite|] ==> (x*y): CInfinite"
    by (auto intro: HInfinite_mult simp add: CInfinite_hcmod_iff hcmod_mult)

    lemma CInfinite_minus_iff [simp]: "(-x ∈ CInfinite) = (x ∈ CInfinite)"
    by (simp add: CInfinite_def)

    lemma CFinite_sum_squares:
         "[|a ∈ CFinite; b ∈ CFinite; c ∈ CFinite|]
          ==> a*a + b*b + c*c ∈ CFinite"
    by (auto intro: CFinite_mult CFinite_add)

    lemma not_CInfinitesimal_not_zero: "x ∉ CInfinitesimal ==> x ≠ 0"
    by auto

    lemma not_CInfinitesimal_not_zero2: "x ∈ CFinite - CInfinitesimal ==> x ≠ 0"
    by auto

    lemma CFinite_diff_CInfinitesimal_hcmod:
         "x ∈ CFinite - CInfinitesimal ==> hcmod x ∈ HFinite - Infinitesimal"
    by (simp add: CFinite_hcmod_iff CInfinitesimal_hcmod_iff)

    lemma hcmod_less_CInfinitesimal:
         "[| e ∈ CInfinitesimal; hcmod x < hcmod e |] ==> x ∈ CInfinitesimal"
    by (auto intro: hrabs_less_Infinitesimal simp add: CInfinitesimal_hcmod_iff)

    lemma hcmod_le_CInfinitesimal:
         "[| e ∈ CInfinitesimal; hcmod x ≤ hcmod e |] ==> x ∈ CInfinitesimal"
    by (auto intro: hrabs_le_Infinitesimal simp add: CInfinitesimal_hcmod_iff)

    lemma CInfinitesimal_interval:
         "[| e ∈ CInfinitesimal;
              e' ∈ CInfinitesimal;
              hcmod e' < hcmod x ; hcmod x < hcmod e
           |] ==> x ∈ CInfinitesimal"
    by (auto intro: Infinitesimal_interval simp add: CInfinitesimal_hcmod_iff)

    lemma CInfinitesimal_interval2:
         "[| e ∈ CInfinitesimal;
             e' ∈ CInfinitesimal;
             hcmod e' ≤ hcmod x ; hcmod x ≤ hcmod e
          |] ==> x ∈ CInfinitesimal"
    by (auto intro: Infinitesimal_interval2 simp add: CInfinitesimal_hcmod_iff)

    lemma not_CInfinitesimal_mult:
         "[| x ∉ CInfinitesimal;  y ∉ CInfinitesimal|] ==> (x*y) ∉ CInfinitesimal"
    apply (auto simp add: CInfinitesimal_hcmod_iff hcmod_mult)
    apply (drule not_Infinitesimal_mult, auto)
    done

    lemma CInfinitesimal_mult_disj:
         "x*y ∈ CInfinitesimal ==> x ∈ CInfinitesimal | y ∈ CInfinitesimal"
    by (auto dest: Infinitesimal_mult_disj simp add: CInfinitesimal_hcmod_iff hcmod_mult)

    lemma CFinite_CInfinitesimal_diff_mult:
         "[| x ∈ CFinite - CInfinitesimal; y ∈ CFinite - CInfinitesimal |]
          ==> x*y ∈ CFinite - CInfinitesimal"
    by (blast dest: CFinite_mult not_CInfinitesimal_mult)

    lemma CInfinitesimal_subset_CFinite: "CInfinitesimal ≤ CFinite"
    by (auto intro: Infinitesimal_subset_HFinite [THEN subsetD]
             simp add: CInfinitesimal_hcmod_iff CFinite_hcmod_iff)

    lemma CInfinitesimal_hcomplex_of_complex_mult:
         "x ∈ CInfinitesimal ==> x * hcomplex_of_complex r ∈ CInfinitesimal"
    by (auto intro!: Infinitesimal_HFinite_mult simp add: CInfinitesimal_hcmod_iff hcmod_mult)

    lemma CInfinitesimal_hcomplex_of_complex_mult2:
         "x ∈ CInfinitesimal ==> hcomplex_of_complex r * x ∈ CInfinitesimal"
    by (auto intro!: Infinitesimal_HFinite_mult2 simp add: CInfinitesimal_hcmod_iff hcmod_mult)

    subsection{*The ``Infinitely Close'' Relation*}

    (*
    Goalw [capprox_def,approx_def] "(z @c= w) = (hcmod z @= hcmod w)"
    by (auto_tac (claset(),simpset() addsimps [CInfinitesimal_hcmod_iff]));
    *)

    lemma mem_cinfmal_iff: "x:CInfinitesimal = (x @c= 0)"
    by (simp add: CInfinitesimal_hcmod_iff capprox_def)

    lemma capprox_minus_iff: "(x @c= y) = (x + -y @c= 0)"
    by (simp add: capprox_def diff_minus)

    lemma capprox_minus_iff2: "(x @c= y) = (-y + x @c= 0)"
    by (simp add: capprox_def diff_minus add_commute)

    lemma capprox_refl [simp]: "x @c= x"
    by (simp add: capprox_def)

    lemma capprox_sym: "x @c= y ==> y @c= x"
    by (simp add: capprox_def CInfinitesimal_def hcmod_diff_commute)

    lemma capprox_trans: "[| x @c= y; y @c= z |] ==> x @c= z"
    apply (simp add: capprox_def)
    apply (drule CInfinitesimal_add, assumption)
    apply (simp add: diff_minus)
    done

    lemma capprox_trans2: "[| r @c= x; s @c= x |] ==> r @c= s"
    by (blast intro: capprox_sym capprox_trans)

    lemma capprox_trans3: "[| x @c= r; x @c= s|] ==> r @c= s"
    by (blast intro: capprox_sym capprox_trans)

    lemma number_of_capprox_reorient [simp]:
         "(number_of w @c= x) = (x @c= number_of w)"
    by (blast intro: capprox_sym)

    lemma CInfinitesimal_capprox_minus: "(x-y ∈ CInfinitesimal) = (x @c= y)"
    by (simp add: diff_minus capprox_minus_iff [symmetric] mem_cinfmal_iff)

    lemma capprox_monad_iff: "(x @c= y) = (cmonad(x)=cmonad(y))"
    by (auto simp add: cmonad_def dest: capprox_sym elim!: capprox_trans equalityCE)

    lemma Infinitesimal_capprox:
         "[| x ∈ CInfinitesimal; y ∈ CInfinitesimal |] ==> x @c= y"
    apply (simp add: mem_cinfmal_iff)
    apply (blast intro: capprox_trans capprox_sym)
    done

    lemma capprox_add: "[| a @c= b; c @c= d |] ==> a+c @c= b+d"
    apply (simp add: capprox_def diff_minus)
    apply (rule minus_add_distrib [THEN ssubst])
    apply (rule add_assoc [THEN ssubst])
    apply (rule_tac b1 = c in add_left_commute [THEN subst])
    apply (rule add_assoc [THEN subst])
    apply (blast intro: CInfinitesimal_add)
    done

    lemma capprox_minus: "a @c= b ==> -a @c= -b"
    apply (rule capprox_minus_iff [THEN iffD2, THEN capprox_sym])
    apply (drule capprox_minus_iff [THEN iffD1])
    apply (simp add: add_commute)
    done

    lemma capprox_minus2: "-a @c= -b ==> a @c= b"
    by (auto dest: capprox_minus)

    lemma capprox_minus_cancel [simp]: "(-a @c= -b) = (a @c= b)"
    by (blast intro: capprox_minus capprox_minus2)

    lemma capprox_add_minus: "[| a @c= b; c @c= d |] ==> a + -c @c= b + -d"
    by (blast intro!: capprox_add capprox_minus)

    lemma capprox_mult1:
          "[| a @c= b; c ∈ CFinite|] ==> a*c @c= b*c"
    apply (simp add: capprox_def diff_minus)
    apply (simp only: CInfinitesimal_CFinite_mult minus_mult_left left_distrib [symmetric])
    done

    lemma capprox_mult2: "[|a @c= b; c ∈ CFinite|] ==> c*a @c= c*b"
    by (simp add: capprox_mult1 mult_commute)

    lemma capprox_mult_subst:
         "[|u @c= v*x; x @c= y; v ∈ CFinite|] ==> u @c= v*y"
    by (blast intro: capprox_mult2 capprox_trans)

    lemma capprox_mult_subst2:
         "[| u @c= x*v; x @c= y; v ∈ CFinite |] ==> u @c= y*v"
    by (blast intro: capprox_mult1 capprox_trans)

    lemma capprox_mult_subst_SComplex:
         "[| u @c= x*hcomplex_of_complex v; x @c= y |]
          ==> u @c= y*hcomplex_of_complex v"
    by (auto intro: capprox_mult_subst2)

    lemma capprox_eq_imp: "a = b ==> a @c= b"
    by (simp add: capprox_def)

    lemma CInfinitesimal_minus_capprox: "x ∈ CInfinitesimal ==> -x @c= x"
    by (blast intro: CInfinitesimal_minus_iff [THEN iffD2] mem_cinfmal_iff [THEN iffD1] capprox_trans2)

    lemma bex_CInfinitesimal_iff: "(∃y ∈ CInfinitesimal. x - z = y) = (x @c= z)"
    by (unfold capprox_def, blast)

    lemma bex_CInfinitesimal_iff2: "(∃y ∈ CInfinitesimal. x = z + y) = (x @c= z)"
    by (simp add: bex_CInfinitesimal_iff [symmetric], force)

    lemma CInfinitesimal_add_capprox:
         "[| y ∈ CInfinitesimal; x + y = z |] ==> x @c= z"
    apply (rule bex_CInfinitesimal_iff [THEN iffD1])
    apply (drule CInfinitesimal_minus_iff [THEN iffD2])
    apply (simp add: eq_commute compare_rls)
    done

    lemma CInfinitesimal_add_capprox_self: "y ∈ CInfinitesimal ==> x @c= x + y"
    apply (rule bex_CInfinitesimal_iff [THEN iffD1])
    apply (drule CInfinitesimal_minus_iff [THEN iffD2])
    apply (simp add: eq_commute compare_rls)
    done

    lemma CInfinitesimal_add_capprox_self2: "y ∈ CInfinitesimal ==> x @c= y + x"
    by (auto dest: CInfinitesimal_add_capprox_self simp add: add_commute)

    lemma CInfinitesimal_add_minus_capprox_self:
         "y ∈ CInfinitesimal ==> x @c= x + -y"
    by (blast intro!: CInfinitesimal_add_capprox_self CInfinitesimal_minus_iff [THEN iffD2])

    lemma CInfinitesimal_add_cancel:
         "[| y ∈ CInfinitesimal; x+y @c= z|] ==> x @c= z"
    apply (drule_tac x = x in CInfinitesimal_add_capprox_self [THEN capprox_sym])
    apply (erule capprox_trans3 [THEN capprox_sym], assumption)
    done

    lemma CInfinitesimal_add_right_cancel:
         "[| y ∈ CInfinitesimal; x @c= z + y|] ==> x @c= z"
    apply (drule_tac x = z in CInfinitesimal_add_capprox_self2 [THEN capprox_sym])
    apply (erule capprox_trans3 [THEN capprox_sym])
    apply (simp add: add_commute)
    apply (erule capprox_sym)
    done

    lemma capprox_add_left_cancel: "d + b  @c= d + c ==> b @c= c"
    apply (drule capprox_minus_iff [THEN iffD1])
    apply (simp add: minus_add_distrib capprox_minus_iff [symmetric] add_ac)
    done

    lemma capprox_add_right_cancel: "b + d @c= c + d ==> b @c= c"
    apply (rule capprox_add_left_cancel)
    apply (simp add: add_commute)
    done

    lemma capprox_add_mono1: "b @c= c ==> d + b @c= d + c"
    apply (rule capprox_minus_iff [THEN iffD2])
    apply (simp add: capprox_minus_iff [symmetric] add_ac)
    done

    lemma capprox_add_mono2: "b @c= c ==> b + a @c= c + a"
    apply (simp (no_asm_simp) add: add_commute capprox_add_mono1)
    done

    lemma capprox_add_left_iff [iff]: "(a + b @c= a + c) = (b @c= c)"
    by (fast elim: capprox_add_left_cancel capprox_add_mono1)

    lemma capprox_add_right_iff [iff]: "(b + a @c= c + a) = (b @c= c)"
    by (simp add: add_commute)

    lemma capprox_CFinite: "[| x ∈ CFinite; x @c= y |] ==> y ∈ CFinite"
    apply (drule bex_CInfinitesimal_iff2 [THEN iffD2], safe)
    apply (drule CInfinitesimal_subset_CFinite [THEN subsetD, THEN CFinite_minus_iff [THEN iffD2]])
    apply (drule CFinite_add)
    apply (assumption, auto)
    done

    lemma capprox_hcomplex_of_complex_CFinite:
         "x @c= hcomplex_of_complex D ==> x ∈ CFinite"
    by (rule capprox_sym [THEN [2] capprox_CFinite], auto)

    lemma capprox_mult_CFinite:
         "[|a @c= b; c @c= d; b ∈ CFinite; d ∈ CFinite|] ==> a*c @c= b*d"
    apply (rule capprox_trans)
    apply (rule_tac [2] capprox_mult2)
    apply (rule capprox_mult1)
    prefer 2 apply (blast intro: capprox_CFinite capprox_sym, auto)
    done

    lemma capprox_mult_hcomplex_of_complex:
         "[|a @c= hcomplex_of_complex b; c @c= hcomplex_of_complex d |]
          ==> a*c @c= hcomplex_of_complex b * hcomplex_of_complex d"
    apply (blast intro!: capprox_mult_CFinite capprox_hcomplex_of_complex_CFinite CFinite_hcomplex_of_complex)
    done

    lemma capprox_SComplex_mult_cancel_zero:
         "[| a ∈ SComplex; a ≠ 0; a*x @c= 0 |] ==> x @c= 0"
    apply (drule SComplex_inverse [THEN SComplex_subset_CFinite [THEN subsetD]])
    apply (auto dest: capprox_mult2 simp add: mult_assoc [symmetric])
    done

    lemma capprox_mult_SComplex1: "[| a ∈ SComplex; x @c= 0 |] ==> x*a @c= 0"
    by (auto dest: SComplex_subset_CFinite [THEN subsetD] capprox_mult1)

    lemma capprox_mult_SComplex2: "[| a ∈ SComplex; x @c= 0 |] ==> a*x @c= 0"
    by (auto dest: SComplex_subset_CFinite [THEN subsetD] capprox_mult2)

    lemma capprox_mult_SComplex_zero_cancel_iff [simp]:
         "[|a ∈ SComplex; a ≠ 0 |] ==> (a*x @c= 0) = (x @c= 0)"
    by (blast intro: capprox_SComplex_mult_cancel_zero capprox_mult_SComplex2)

    lemma capprox_SComplex_mult_cancel:
         "[| a ∈ SComplex; a ≠ 0; a* w @c= a*z |] ==> w @c= z"
    apply (drule SComplex_inverse [THEN SComplex_subset_CFinite [THEN subsetD]])
    apply (auto dest: capprox_mult2 simp add: mult_assoc [symmetric])
    done

    lemma capprox_SComplex_mult_cancel_iff1 [simp]:
         "[| a ∈ SComplex; a ≠ 0|] ==> (a* w @c= a*z) = (w @c= z)"
    by (auto intro!: capprox_mult2 SComplex_subset_CFinite [THEN subsetD]
                intro: capprox_SComplex_mult_cancel)

    lemma capprox_hcmod_approx_zero: "(x @c= y) = (hcmod (y - x) @= 0)"
    apply (rule capprox_minus_iff [THEN ssubst])
    apply (simp add: capprox_def CInfinitesimal_hcmod_iff mem_infmal_iff diff_minus [symmetric] hcmod_diff_commute)
    done

    lemma capprox_approx_zero_iff: "(x @c= 0) = (hcmod x @= 0)"
    by (simp add: capprox_hcmod_approx_zero)

    lemma capprox_minus_zero_cancel_iff [simp]: "(-x @c= 0) = (x @c= 0)"
    by (simp add: capprox_hcmod_approx_zero)

    lemma Infinitesimal_hcmod_add_diff:
         "u @c= 0 ==> hcmod(x + u) - hcmod x ∈ Infinitesimal"
    apply (rule_tac e = "hcmod u" and e' = "- hcmod u" in Infinitesimal_interval2)
    apply (auto dest: capprox_approx_zero_iff [THEN iffD1]
                 simp add: mem_infmal_iff [symmetric] diff_def)
    apply (rule_tac c1 = "hcmod x" in add_le_cancel_left [THEN iffD1])
    apply (auto simp add: diff_minus [symmetric])
    done

    lemma approx_hcmod_add_hcmod: "u @c= 0 ==> hcmod(x + u) @= hcmod x"
    apply (rule approx_minus_iff [THEN iffD2])
    apply (auto intro: Infinitesimal_hcmod_add_diff simp add: mem_infmal_iff [symmetric] diff_minus [symmetric])
    done

    lemma capprox_hcmod_approx: "x @c= y ==> hcmod x @= hcmod y"
    by (auto intro: approx_hcmod_add_hcmod
             dest!: bex_CInfinitesimal_iff2 [THEN iffD2]
             simp add: mem_cinfmal_iff)

    subsection{*Zero is the Only Infinitesimal Complex Number*}

    lemma CInfinitesimal_less_SComplex:
       "[| x ∈ SComplex; y ∈ CInfinitesimal; 0 < hcmod x |] ==> hcmod y < hcmod x"
    by (auto intro!: Infinitesimal_less_SReal SComplex_hcmod_SReal simp add: CInfinitesimal_hcmod_iff)

    lemma SComplex_Int_CInfinitesimal_zero: "SComplex Int CInfinitesimal = {0}"
    apply (auto simp add: SComplex_def CInfinitesimal_hcmod_iff)
    apply (cut_tac r = r in SReal_hcmod_hcomplex_of_complex)
    apply (drule_tac A = Reals in IntI, assumption)
    apply (subgoal_tac "hcmod (hcomplex_of_complex r) = 0")
    apply simp
    apply (simp add: SReal_Int_Infinitesimal_zero)
    done

    lemma SComplex_CInfinitesimal_zero:
         "[| x ∈ SComplex; x ∈ CInfinitesimal|] ==> x = 0"
    by (cut_tac SComplex_Int_CInfinitesimal_zero, blast)

    lemma SComplex_CFinite_diff_CInfinitesimal:
         "[| x ∈ SComplex; x ≠ 0 |] ==> x ∈ CFinite - CInfinitesimal"
    by (auto dest: SComplex_CInfinitesimal_zero SComplex_subset_CFinite [THEN subsetD])

    lemma hcomplex_of_complex_CFinite_diff_CInfinitesimal:
         "hcomplex_of_complex x ≠ 0
          ==> hcomplex_of_complex x ∈ CFinite - CInfinitesimal"
    by (rule SComplex_CFinite_diff_CInfinitesimal, auto)

    lemma hcomplex_of_complex_CInfinitesimal_iff_0 [iff]:
         "(hcomplex_of_complex x ∈ CInfinitesimal) = (x=0)"
    apply (auto)
    apply (rule ccontr)
    apply (rule hcomplex_of_complex_CFinite_diff_CInfinitesimal [THEN DiffD2], auto)
    done

    lemma number_of_not_CInfinitesimal [simp]:
         "number_of w ≠ (0::hcomplex) ==> number_of w ∉ CInfinitesimal"
    by (fast dest: SComplex_number_of [THEN SComplex_CInfinitesimal_zero])

    lemma capprox_SComplex_not_zero:
         "[| y ∈ SComplex; x @c= y; y≠ 0 |] ==> x ≠ 0"
    by (auto dest: SComplex_CInfinitesimal_zero capprox_sym [THEN mem_cinfmal_iff [THEN iffD2]])

    lemma CFinite_diff_CInfinitesimal_capprox:
         "[| x @c= y; y ∈ CFinite - CInfinitesimal |]
          ==> x ∈ CFinite - CInfinitesimal"
    apply (auto intro: capprox_sym [THEN [2] capprox_CFinite]
                simp add: mem_cinfmal_iff)
    apply (drule capprox_trans3, assumption)
    apply (blast dest: capprox_sym)
    done

    lemma CInfinitesimal_ratio:
         "[| y ≠ 0;  y ∈ CInfinitesimal;  x/y ∈ CFinite |] ==> x ∈ CInfinitesimal"
    apply (drule CInfinitesimal_CFinite_mult2, assumption)
    apply (simp add: divide_inverse mult_assoc)
    done

    lemma SComplex_capprox_iff:
         "[|x ∈ SComplex; y ∈ SComplex|] ==> (x @c= y) = (x = y)"
    apply auto
    apply (simp add: capprox_def)
    apply (subgoal_tac "x-y = 0", simp)
    apply (rule SComplex_CInfinitesimal_zero)
    apply (simp add: SComplex_diff, assumption)
    done

    lemma number_of_capprox_iff [simp]:
        "(number_of v @c= number_of w) = (number_of v = (number_of w :: hcomplex))"
    by (rule SComplex_capprox_iff, auto)

    lemma number_of_CInfinitesimal_iff [simp]:
         "(number_of w ∈ CInfinitesimal) = (number_of w = (0::hcomplex))"
    apply (rule iffI)
    apply (fast dest: SComplex_number_of [THEN SComplex_CInfinitesimal_zero])
    apply (simp (no_asm_simp))
    done

    lemma hcomplex_of_complex_approx_iff [simp]:
         "(hcomplex_of_complex k @c= hcomplex_of_complex m) = (k = m)"
    apply auto
    apply (rule inj_hcomplex_of_complex [THEN injD])
    apply (rule SComplex_capprox_iff [THEN iffD1], auto)
    done

    lemma hcomplex_of_complex_capprox_number_of_iff [simp]:
         "(hcomplex_of_complex k @c= number_of w) = (k = number_of w)"
    by (subst hcomplex_of_complex_approx_iff [symmetric], auto)

    lemma capprox_unique_complex:
         "[| r ∈ SComplex; s ∈ SComplex; r @c= x; s @c= x|] ==> r = s"
    by (blast intro: SComplex_capprox_iff [THEN iffD1] capprox_trans2)

    lemma hcomplex_capproxD1:
         "star_n X @c= star_n Y
          ==> star_n (%n. Re(X n)) @= star_n (%n. Re(Y n))"
    apply (auto simp add: approx_FreeUltrafilterNat_iff)
    apply (drule capprox_minus_iff [THEN iffD1])
    apply (auto simp add: star_n_minus star_n_add mem_cinfmal_iff [symmetric] CInfinitesimal_hcmod_iff hcmod Infinitesimal_FreeUltrafilterNat_iff2)
    apply (drule_tac x = m in spec, ultra)
    apply (rename_tac Z x)
    apply (case_tac "X x")
    apply (case_tac "Y x")
    apply (auto simp add: complex_minus complex_add complex_mod
               simp del: realpow_Suc)
    apply (rule_tac y="abs(Z x)" in order_le_less_trans)
    apply (drule_tac t = "Z x" in sym)
    apply (auto simp del: realpow_Suc)
    done

    (* same proof *)
    lemma hcomplex_capproxD2:
         "star_n X @c= star_n Y
          ==> star_n (%n. Im(X n)) @= star_n (%n. Im(Y n))"
    apply (auto simp add: approx_FreeUltrafilterNat_iff)
    apply (drule capprox_minus_iff [THEN iffD1])
    apply (auto simp add: star_n_minus star_n_add mem_cinfmal_iff [symmetric] CInfinitesimal_hcmod_iff hcmod Infinitesimal_FreeUltrafilterNat_iff2)
    apply (drule_tac x = m in spec, ultra)
    apply (rename_tac Z x)
    apply (case_tac "X x")
    apply (case_tac "Y x")
    apply (auto simp add: complex_minus complex_add complex_mod simp del: realpow_Suc)
    apply (rule_tac y="abs(Z x)" in order_le_less_trans)
    apply (drule_tac t = "Z x" in sym)
    apply (auto simp del: realpow_Suc)
    done

    lemma hcomplex_capproxI:
         "[| star_n (%n. Re(X n)) @= star_n (%n. Re(Y n));
             star_n (%n. Im(X n)) @= star_n (%n. Im(Y n))
          |] ==> star_n X @c= star_n Y"
    apply (drule approx_minus_iff [THEN iffD1])
    apply (drule approx_minus_iff [THEN iffD1])
    apply (rule capprox_minus_iff [THEN iffD2])
    apply (auto simp add: mem_cinfmal_iff [symmetric] mem_infmal_iff [symmetric] star_n_add star_n_minus CInfinitesimal_hcmod_iff hcmod Infinitesimal_FreeUltrafilterNat_iff)
    apply (rule bexI [OF _ Rep_star_star_n], auto)
    apply (drule_tac x = "u/2" in spec)
    apply (drule_tac x = "u/2" in spec, auto, ultra)
    apply (drule sym, drule sym)
    apply (case_tac "X x")
    apply (case_tac "Y x")
    apply (auto simp add: complex_minus complex_add complex_mod snd_conv fst_conv numeral_2_eq_2)
    apply (rename_tac a b c d)
    apply (subgoal_tac "sqrt (abs (a + - c) ^ 2 + abs (b + - d) ^ 2) < u")
    apply (rule_tac [2] lemma_sqrt_hcomplex_capprox, auto)
    apply (simp add: power2_eq_square)
    done

    lemma capprox_approx_iff:
         "(star_n X @c= star_n Y) =
           (star_n (%n. Re(X n)) @= star_n (%n. Re(Y n)) &
            star_n (%n. Im(X n)) @= star_n (%n. Im(Y n)))"
    apply (blast intro: hcomplex_capproxI hcomplex_capproxD1 hcomplex_capproxD2)
    done

    lemma hcomplex_of_hypreal_capprox_iff [simp]:
         "(hcomplex_of_hypreal x @c= hcomplex_of_hypreal z) = (x @= z)"
    apply (cases x, cases z)
    apply (simp add: hcomplex_of_hypreal capprox_approx_iff)
    done

    lemma CFinite_HFinite_Re:
         "star_n X ∈ CFinite
          ==> star_n (%n. Re(X n)) ∈ HFinite"
    apply (auto simp add: CFinite_hcmod_iff hcmod HFinite_FreeUltrafilterNat_iff)
    apply (rule bexI [OF _ Rep_star_star_n])
    apply (rule_tac x = u in exI, ultra)
    apply (drule sym, case_tac "X x")
    apply (auto simp add: complex_mod numeral_2_eq_2 simp del: realpow_Suc)
    apply (rule ccontr, drule linorder_not_less [THEN iffD1])
    apply (drule order_less_le_trans, assumption)
    apply (drule real_sqrt_ge_abs1 [THEN [2] order_less_le_trans])
    apply (auto simp add: numeral_2_eq_2 [symmetric])
    done

    lemma CFinite_HFinite_Im:
         "star_n X ∈ CFinite
          ==> star_n (%n. Im(X n)) ∈ HFinite"
    apply (auto simp add: CFinite_hcmod_iff hcmod HFinite_FreeUltrafilterNat_iff)
    apply (rule bexI [OF _ Rep_star_star_n])
    apply (rule_tac x = u in exI, ultra)
    apply (drule sym, case_tac "X x")
    apply (auto simp add: complex_mod simp del: realpow_Suc)
    apply (rule ccontr, drule linorder_not_less [THEN iffD1])
    apply (drule order_less_le_trans, assumption)
    apply (drule real_sqrt_ge_abs2 [THEN [2] order_less_le_trans], auto)
    done

    lemma HFinite_Re_Im_CFinite:
         "[| star_n (%n. Re(X n)) ∈ HFinite;
             star_n (%n. Im(X n)) ∈ HFinite
          |] ==> star_n X ∈ CFinite"
    apply (auto simp add: CFinite_hcmod_iff hcmod HFinite_FreeUltrafilterNat_iff)
    apply (rename_tac Y Z u v)
    apply (rule bexI [OF _ Rep_star_star_n])
    apply (rule_tac x = "2* (u + v) " in exI)
    apply ultra
    apply (drule sym, case_tac "X x")
    apply (auto simp add: complex_mod numeral_2_eq_2 simp del: realpow_Suc)
    apply (subgoal_tac "0 < u")
     prefer 2 apply arith
    apply (subgoal_tac "0 < v")
     prefer 2 apply arith
    apply (subgoal_tac "sqrt (abs (Y x) ^ 2 + abs (Z x) ^ 2) < 2*u + 2*v")
    apply (rule_tac [2] lemma_sqrt_hcomplex_capprox, auto)
    apply (simp add: power2_eq_square)
    done

    lemma CFinite_HFinite_iff:
         "(star_n X ∈ CFinite) =
          (star_n (%n. Re(X n)) ∈ HFinite &
           star_n (%n. Im(X n)) ∈ HFinite)"
    by (blast intro: HFinite_Re_Im_CFinite CFinite_HFinite_Im CFinite_HFinite_Re)

    lemma SComplex_Re_SReal:
         "star_n X ∈ SComplex
          ==> star_n (%n. Re(X n)) ∈ Reals"
    apply (auto simp add: SComplex_def SReal_def star_of_def star_n_eq_iff)
    apply (rule_tac x = "Re r" in exI, ultra)
    done

    lemma SComplex_Im_SReal:
         "star_n X ∈ SComplex
          ==> star_n (%n. Im(X n)) ∈ Reals"
    apply (auto simp add: SComplex_def SReal_def star_of_def star_n_eq_iff)
    apply (rule_tac x = "Im r" in exI, ultra)
    done

    lemma Reals_Re_Im_SComplex:
         "[| star_n (%n. Re(X n)) ∈ Reals;
             star_n (%n. Im(X n)) ∈ Reals
          |] ==> star_n X ∈ SComplex"
    apply (auto simp add: SComplex_def SReal_def star_of_def star_n_eq_iff)
    apply (rule_tac x = "Complex r ra" in exI, ultra)
    done

    lemma SComplex_SReal_iff:
         "(star_n X ∈ SComplex) =
          (star_n (%n. Re(X n)) ∈ Reals &
           star_n (%n. Im(X n)) ∈ Reals)"
    by (blast intro: SComplex_Re_SReal SComplex_Im_SReal Reals_Re_Im_SComplex)

    lemma CInfinitesimal_Infinitesimal_iff:
         "(star_n X ∈ CInfinitesimal) =
          (star_n (%n. Re(X n)) ∈ Infinitesimal &
           star_n (%n. Im(X n)) ∈ Infinitesimal)"
    by (simp add: mem_cinfmal_iff mem_infmal_iff star_n_zero_num capprox_approx_iff)

    lemma eq_Abs_star_EX:
         "(∃t. P t) = (∃X. P (star_n X))"
    by (rule ex_star_eq)

    lemma eq_Abs_star_Bex:
         "(∃t ∈ A. P t) = (∃X. star_n X ∈ A & P (star_n X))"
    by (simp add: Bex_def ex_star_eq)

    (* Here we go - easy proof now!! *)
    lemma stc_part_Ex: "x:CFinite ==> ∃t ∈ SComplex. x @c= t"
    apply (cases x)
    apply (auto simp add: CFinite_HFinite_iff eq_Abs_star_Bex SComplex_SReal_iff capprox_approx_iff)
    apply (drule st_part_Ex, safe)+
    apply (rule_tac x = t in star_cases)
    apply (rule_tac x = ta in star_cases, auto)
    apply (rule_tac x = "%n. Complex (Xa n) (Xb n) " in exI)
    apply auto
    done

    lemma stc_part_Ex1: "x:CFinite ==> EX! t. t ∈ SComplex &  x @c= t"
    apply (drule stc_part_Ex, safe)
    apply (drule_tac [2] capprox_sym, drule_tac [2] capprox_sym, drule_tac [2] capprox_sym)
    apply (auto intro!: capprox_unique_complex)
    done

    lemma CFinite_Int_CInfinite_empty: "CFinite Int CInfinite = {}"
    by (simp add: CFinite_def CInfinite_def, auto)

    lemma CFinite_not_CInfinite: "x ∈ CFinite ==> x ∉ CInfinite"
    by (insert CFinite_Int_CInfinite_empty, blast)

    text{*Not sure this is a good idea!*}
    declare CFinite_Int_CInfinite_empty [simp]

    lemma not_CFinite_CInfinite: "x∉ CFinite ==> x ∈ CInfinite"
    by (auto intro: not_HFinite_HInfinite simp add: CFinite_hcmod_iff CInfinite_hcmod_iff)

    lemma CInfinite_CFinite_disj: "x ∈ CInfinite | x ∈ CFinite"
    by (blast intro: not_CFinite_CInfinite)

    lemma CInfinite_CFinite_iff: "(x ∈ CInfinite) = (x ∉ CFinite)"
    by (blast dest: CFinite_not_CInfinite not_CFinite_CInfinite)

    lemma CFinite_CInfinite_iff: "(x ∈ CFinite) = (x ∉ CInfinite)"
    by (simp add: CInfinite_CFinite_iff)

    lemma CInfinite_diff_CFinite_CInfinitesimal_disj:
         "x ∉ CInfinitesimal ==> x ∈ CInfinite | x ∈ CFinite - CInfinitesimal"
    by (fast intro: not_CFinite_CInfinite)

    lemma CFinite_inverse:
         "[| x ∈ CFinite; x ∉ CInfinitesimal |] ==> inverse x ∈ CFinite"
    apply (cut_tac x = "inverse x" in CInfinite_CFinite_disj)
    apply (auto dest!: CInfinite_inverse_CInfinitesimal)
    done

    lemma CFinite_inverse2: "x ∈ CFinite - CInfinitesimal ==> inverse x ∈ CFinite"
    by (blast intro: CFinite_inverse)

    lemma CInfinitesimal_inverse_CFinite:
         "x ∉ CInfinitesimal ==> inverse(x) ∈ CFinite"
    apply (drule CInfinite_diff_CFinite_CInfinitesimal_disj)
    apply (blast intro: CFinite_inverse CInfinite_inverse_CInfinitesimal CInfinitesimal_subset_CFinite [THEN subsetD])
    done

    lemma CFinite_not_CInfinitesimal_inverse:
         "x ∈ CFinite - CInfinitesimal ==> inverse x ∈ CFinite - CInfinitesimal"
    apply (auto intro: CInfinitesimal_inverse_CFinite)
    apply (drule CInfinitesimal_CFinite_mult2, assumption)
    apply (simp add: not_CInfinitesimal_not_zero)
    done

    lemma capprox_inverse:
         "[| x @c= y; y ∈  CFinite - CInfinitesimal |] ==> inverse x @c= inverse y"
    apply (frule CFinite_diff_CInfinitesimal_capprox, assumption)
    apply (frule not_CInfinitesimal_not_zero2)
    apply (frule_tac x = x in not_CInfinitesimal_not_zero2)
    apply (drule CFinite_inverse2)+
    apply (drule capprox_mult2, assumption, auto)
    apply (drule_tac c = "inverse x" in capprox_mult1, assumption)
    apply (auto intro: capprox_sym simp add: mult_assoc)
    done

    lemmas hcomplex_of_complex_capprox_inverse =
      hcomplex_of_complex_CFinite_diff_CInfinitesimal [THEN [2] capprox_inverse]

    lemma inverse_add_CInfinitesimal_capprox:
         "[| x ∈ CFinite - CInfinitesimal;
             h ∈ CInfinitesimal |] ==> inverse(x + h) @c= inverse x"
    by (auto intro: capprox_inverse capprox_sym CInfinitesimal_add_capprox_self)

    lemma inverse_add_CInfinitesimal_capprox2:
         "[| x ∈ CFinite - CInfinitesimal;
             h ∈ CInfinitesimal |] ==> inverse(h + x) @c= inverse x"
    apply (rule add_commute [THEN subst])
    apply (blast intro: inverse_add_CInfinitesimal_capprox)
    done

    lemma inverse_add_CInfinitesimal_approx_CInfinitesimal:
         "[| x ∈ CFinite - CInfinitesimal;
             h ∈ CInfinitesimal |] ==> inverse(x + h) - inverse x @c= h"
    apply (rule capprox_trans2)
    apply (auto intro: inverse_add_CInfinitesimal_capprox
           simp add: mem_cinfmal_iff diff_minus capprox_minus_iff [symmetric])
    done

    lemma CInfinitesimal_square_iff [iff]:
         "(x*x ∈ CInfinitesimal) = (x ∈ CInfinitesimal)"
    by (simp add: CInfinitesimal_hcmod_iff hcmod_mult)

    lemma capprox_CFinite_mult_cancel:
         "[| a ∈ CFinite-CInfinitesimal; a*w @c= a*z |] ==> w @c= z"
    apply safe
    apply (frule CFinite_inverse, assumption)
    apply (drule not_CInfinitesimal_not_zero)
    apply (auto dest: capprox_mult2 simp add: mult_assoc [symmetric])
    done

    lemma capprox_CFinite_mult_cancel_iff1:
         "a ∈ CFinite-CInfinitesimal ==> (a * w @c= a * z) = (w @c= z)"
    by (auto intro: capprox_mult2 capprox_CFinite_mult_cancel)

    subsection{*Theorems About Monads*}

    lemma capprox_cmonad_iff: "(x @c= y) = (cmonad(x)=cmonad(y))"
    apply (simp add: cmonad_def)
    apply (auto dest: capprox_sym elim!: capprox_trans equalityCE)
    done

    lemma CInfinitesimal_cmonad_eq:
         "e ∈ CInfinitesimal ==> cmonad (x+e) = cmonad x"
    by (fast intro!: CInfinitesimal_add_capprox_self [THEN capprox_sym] capprox_cmonad_iff [THEN iffD1])

    lemma mem_cmonad_iff: "(u ∈ cmonad x) = (-u ∈ cmonad (-x))"
    by (simp add: cmonad_def)

    lemma CInfinitesimal_cmonad_zero_iff: "(x:CInfinitesimal) = (x ∈ cmonad 0)"
    by (auto intro: capprox_sym simp add: mem_cinfmal_iff cmonad_def)

    lemma cmonad_zero_minus_iff: "(x ∈ cmonad 0) = (-x ∈ cmonad 0)"
    by (simp add: CInfinitesimal_cmonad_zero_iff [symmetric])

    lemma cmonad_zero_hcmod_iff: "(x ∈ cmonad 0) = (hcmod x:monad 0)"
    by (simp add: CInfinitesimal_cmonad_zero_iff [symmetric] CInfinitesimal_hcmod_iff Infinitesimal_monad_zero_iff [symmetric])

    lemma mem_cmonad_self [simp]: "x ∈ cmonad x"
    by (simp add: cmonad_def)

    subsection{*Theorems About Standard Part*}

    lemma stc_capprox_self: "x ∈ CFinite ==> stc x @c= x"
    apply (simp add: stc_def)
    apply (frule stc_part_Ex, safe)
    apply (rule someI2)
    apply (auto intro: capprox_sym)
    done

    lemma stc_SComplex: "x ∈ CFinite ==> stc x ∈ SComplex"
    apply (simp add: stc_def)
    apply (frule stc_part_Ex, safe)
    apply (rule someI2)
    apply (auto intro: capprox_sym)
    done

    lemma stc_CFinite: "x ∈ CFinite ==> stc x ∈ CFinite"
    by (erule stc_SComplex [THEN SComplex_subset_CFinite [THEN subsetD]])

    lemma stc_SComplex_eq [simp]: "x ∈ SComplex ==> stc x = x"
    apply (simp add: stc_def)
    apply (rule some_equality)
    apply (auto intro: SComplex_subset_CFinite [THEN subsetD])
    apply (blast dest: SComplex_capprox_iff [THEN iffD1])
    done

    lemma stc_hcomplex_of_complex:
         "stc (hcomplex_of_complex x) = hcomplex_of_complex x"
    by auto

    lemma stc_eq_capprox:
         "[| x ∈ CFinite; y ∈ CFinite; stc x = stc y |] ==> x @c= y"
    by (auto dest!: stc_capprox_self elim!: capprox_trans3)

    lemma capprox_stc_eq:
         "[| x ∈ CFinite; y ∈ CFinite; x @c= y |] ==> stc x = stc y"
    by (blast intro: capprox_trans capprox_trans2 SComplex_capprox_iff [THEN iffD1]
              dest: stc_capprox_self stc_SComplex)

    lemma stc_eq_capprox_iff:
         "[| x ∈ CFinite; y ∈ CFinite|] ==> (x @c= y) = (stc x = stc y)"
    by (blast intro: capprox_stc_eq stc_eq_capprox)

    lemma stc_CInfinitesimal_add_SComplex:
         "[| x ∈ SComplex; e ∈ CInfinitesimal |] ==> stc(x + e) = x"
    apply (frule stc_SComplex_eq [THEN subst])
    prefer 2 apply assumption
    apply (frule SComplex_subset_CFinite [THEN subsetD])
    apply (frule CInfinitesimal_subset_CFinite [THEN subsetD])
    apply (drule stc_SComplex_eq)
    apply (rule capprox_stc_eq)
    apply (auto intro: CFinite_add simp add: CInfinitesimal_add_capprox_self [THEN capprox_sym])
    done

    lemma stc_CInfinitesimal_add_SComplex2:
         "[| x ∈ SComplex; e ∈ CInfinitesimal |] ==> stc(e + x) = x"
    apply (rule add_commute [THEN subst])
    apply (blast intro!: stc_CInfinitesimal_add_SComplex)
    done

    lemma CFinite_stc_CInfinitesimal_add:
         "x ∈ CFinite ==> ∃e ∈ CInfinitesimal. x = stc(x) + e"
    by (blast dest!: stc_capprox_self [THEN capprox_sym] bex_CInfinitesimal_iff2 [THEN iffD2])

    lemma stc_add:
         "[| x ∈ CFinite; y ∈ CFinite |] ==> stc (x + y) = stc(x) + stc(y)"
    apply (frule CFinite_stc_CInfinitesimal_add)
    apply (frule_tac x = y in CFinite_stc_CInfinitesimal_add, safe)
    apply (subgoal_tac "stc (x + y) = stc ((stc x + e) + (stc y + ea))")
    apply (drule_tac [2] sym, drule_tac [2] sym)
     prefer 2 apply simp
    apply (simp (no_asm_simp) add: add_ac)
    apply (drule stc_SComplex)+
    apply (drule SComplex_add, assumption)
    apply (drule CInfinitesimal_add, assumption)
    apply (rule add_assoc [THEN subst])
    apply (blast intro!: stc_CInfinitesimal_add_SComplex2)
    done

    lemma stc_number_of [simp]: "stc (number_of w) = number_of w"
    by (rule SComplex_number_of [THEN stc_SComplex_eq])

    lemma stc_zero [simp]: "stc 0 = 0"
    by simp

    lemma stc_one [simp]: "stc 1 = 1"
    by simp

    lemma stc_minus: "y ∈ CFinite ==> stc(-y) = -stc(y)"
    apply (frule CFinite_minus_iff [THEN iffD2])
    apply (rule hcomplex_add_minus_eq_minus)
    apply (drule stc_add [symmetric], assumption)
    apply (simp add: add_commute)
    done

    lemma stc_diff:
         "[| x ∈ CFinite; y ∈ CFinite |] ==> stc (x-y) = stc(x) - stc(y)"
    apply (simp add: diff_minus)
    apply (frule_tac y1 = y in stc_minus [symmetric])
    apply (drule_tac x1 = y in CFinite_minus_iff [THEN iffD2])
    apply (auto intro: stc_add)
    done

    lemma lemma_stc_mult:
         "[| x ∈ CFinite; y ∈ CFinite;
             e ∈ CInfinitesimal;
             ea: CInfinitesimal |]
           ==> e*y + x*ea + e*ea: CInfinitesimal"
    apply (frule_tac x = e and y = y in CInfinitesimal_CFinite_mult)
    apply (frule_tac [2] x = ea and y = x in CInfinitesimal_CFinite_mult)
    apply (drule_tac [3] CInfinitesimal_mult)
    apply (auto intro: CInfinitesimal_add simp add: add_ac mult_ac)
    done

    lemma stc_mult:
         "[| x ∈ CFinite; y ∈ CFinite |]
                   ==> stc (x * y) = stc(x) * stc(y)"
    apply (frule CFinite_stc_CInfinitesimal_add)
    apply (frule_tac x = y in CFinite_stc_CInfinitesimal_add, safe)
    apply (subgoal_tac "stc (x * y) = stc ((stc x + e) * (stc y + ea))")
    apply (drule_tac [2] sym, drule_tac [2] sym)
     prefer 2 apply simp
    apply (erule_tac V = "x = stc x + e" in thin_rl)
    apply (erule_tac V = "y = stc y + ea" in thin_rl)
    apply (simp add: left_distrib right_distrib)
    apply (drule stc_SComplex)+
    apply (simp (no_asm_use) add: add_assoc)
    apply (rule stc_CInfinitesimal_add_SComplex)
    apply (blast intro!: SComplex_mult)
    apply (drule SComplex_subset_CFinite [THEN subsetD])+
    apply (rule add_assoc [THEN subst])
    apply (blast intro!: lemma_stc_mult)
    done

    lemma stc_CInfinitesimal: "x ∈ CInfinitesimal ==> stc x = 0"
    apply (rule stc_zero [THEN subst])
    apply (rule capprox_stc_eq)
    apply (auto intro: CInfinitesimal_subset_CFinite [THEN subsetD]
                     simp add: mem_cinfmal_iff [symmetric])
    done

    lemma stc_not_CInfinitesimal: "stc(x) ≠ 0 ==> x ∉ CInfinitesimal"
    by (fast intro: stc_CInfinitesimal)

    lemma stc_inverse:
         "[| x ∈ CFinite; stc x ≠ 0 |]
          ==> stc(inverse x) = inverse (stc x)"
    apply (rule_tac c1 = "stc x" in hcomplex_mult_left_cancel [THEN iffD1])
    apply (auto simp add: stc_mult [symmetric] stc_not_CInfinitesimal CFinite_inverse)
    apply (subst right_inverse, auto)
    done

    lemma stc_divide [simp]:
         "[| x ∈ CFinite; y ∈ CFinite; stc y ≠ 0 |]
          ==> stc(x/y) = (stc x) / (stc y)"
    by (simp add: divide_inverse stc_mult stc_not_CInfinitesimal CFinite_inverse stc_inverse)

    lemma stc_idempotent [simp]: "x ∈ CFinite ==> stc(stc(x)) = stc(x)"
    by (blast intro: stc_CFinite stc_capprox_self capprox_stc_eq)

    lemma CFinite_HFinite_hcomplex_of_hypreal:
         "z ∈ HFinite ==> hcomplex_of_hypreal z ∈ CFinite"
    apply (cases z)
    apply (simp add: hcomplex_of_hypreal CFinite_HFinite_iff star_n_zero_num [symmetric])
    done

    lemma SComplex_SReal_hcomplex_of_hypreal:
         "x ∈ Reals ==>  hcomplex_of_hypreal x ∈ SComplex"
    by (auto simp add: SReal_def SComplex_def hcomplex_of_hypreal_def)

    lemma stc_hcomplex_of_hypreal:
     "z ∈ HFinite ==> stc(hcomplex_of_hypreal z) = hcomplex_of_hypreal (st z)"
    apply (simp add: st_def stc_def)
    apply (frule st_part_Ex, safe)
    apply (rule someI2)
    apply (auto intro: approx_sym)
    apply (drule CFinite_HFinite_hcomplex_of_hypreal)
    apply (frule stc_part_Ex, safe)
    apply (rule someI2)
    apply (auto intro: capprox_sym intro!: capprox_unique_complex dest: SComplex_SReal_hcomplex_of_hypreal)
    done

    (*
    Goal "x ∈ CFinite ==> hcmod(stc x) = st(hcmod x)"
    by (dtac stc_capprox_self 1)
    by (auto_tac (claset(),simpset() addsimps [bex_CInfinitesimal_iff2 RS sym]));

    approx_hcmod_add_hcmod
    *)

    lemma CInfinitesimal_hcnj_iff [simp]:
         "(hcnj z ∈ CInfinitesimal) = (z ∈ CInfinitesimal)"
    by (simp add: CInfinitesimal_hcmod_iff)

    lemma CInfinite_HInfinite_iff:
         "(star_n X ∈ CInfinite) =
          (star_n (%n. Re(X n)) ∈ HInfinite |
           star_n (%n. Im(X n)) ∈ HInfinite)"
    by (simp add: CInfinite_CFinite_iff HInfinite_HFinite_iff CFinite_HFinite_iff)

    text{*These theorems should probably be deleted*}
    lemma hcomplex_split_CInfinitesimal_iff:
         "(hcomplex_of_hypreal x + iii * hcomplex_of_hypreal y ∈ CInfinitesimal) =
          (x ∈ Infinitesimal & y ∈ Infinitesimal)"
    apply (cases x, cases y)
    apply (simp add: iii_def star_of_def star_n_add star_n_mult hcomplex_of_hypreal CInfinitesimal_Infinitesimal_iff)
    done

    lemma hcomplex_split_CFinite_iff:
         "(hcomplex_of_hypreal x + iii * hcomplex_of_hypreal y ∈ CFinite) =
          (x ∈ HFinite & y ∈ HFinite)"
    apply (cases x, cases y)
    apply (simp add: iii_def star_of_def star_n_add star_n_mult hcomplex_of_hypreal CFinite_HFinite_iff)
    done

    lemma hcomplex_split_SComplex_iff:
         "(hcomplex_of_hypreal x + iii * hcomplex_of_hypreal y ∈ SComplex) =
          (x ∈ Reals & y ∈ Reals)"
    apply (cases x, cases y)
    apply (simp add: iii_def star_of_def star_n_add star_n_mult hcomplex_of_hypreal SComplex_SReal_iff)
    done

    lemma hcomplex_split_CInfinite_iff:
         "(hcomplex_of_hypreal x + iii * hcomplex_of_hypreal y ∈ CInfinite) =
          (x ∈ HInfinite | y ∈ HInfinite)"
    apply (cases x, cases y)
    apply (simp add: iii_def star_of_def star_n_add star_n_mult hcomplex_of_hypreal CInfinite_HInfinite_iff)
    done

    lemma hcomplex_split_capprox_iff:
         "(hcomplex_of_hypreal x + iii * hcomplex_of_hypreal y @c=
           hcomplex_of_hypreal x' + iii * hcomplex_of_hypreal y') =
          (x @= x' & y @= y')"
    apply (cases x, cases y, cases x', cases y')
    apply (simp add: iii_def star_of_def star_n_add star_n_mult hcomplex_of_hypreal capprox_approx_iff)
    done

    lemma complex_seq_to_hcomplex_CInfinitesimal:
         "∀n. cmod (X n - x) < inverse (real (Suc n)) ==>
          star_n X - hcomplex_of_complex x ∈ CInfinitesimal"
    apply (simp add: star_n_diff CInfinitesimal_hcmod_iff star_of_def Infinitesimal_FreeUltrafilterNat_iff hcmod)
    apply (rule bexI, auto)
    apply (auto dest: FreeUltrafilterNat_inverse_real_of_posnat FreeUltrafilterNat_all FreeUltrafilterNat_Int intro: order_less_trans FreeUltrafilterNat_subset)
    done

    lemma CInfinitesimal_hcomplex_of_hypreal_epsilon [simp]:
         "hcomplex_of_hypreal epsilon ∈ CInfinitesimal"
    by (simp add: CInfinitesimal_hcmod_iff)

    lemma hcomplex_of_complex_approx_zero_iff [simp]:
         "(hcomplex_of_complex z @c= 0) = (z = 0)"
    by (simp add: star_of_zero [symmetric] del: star_of_zero)

    lemma hcomplex_of_complex_approx_zero_iff2 [simp]:
         "(0 @c= hcomplex_of_complex z) = (z = 0)"
    by (simp add: star_of_zero [symmetric] del: star_of_zero)

    ML
    {*
    val SComplex_add = thm "SComplex_add";
    val SComplex_mult = thm "SComplex_mult";
    val SComplex_inverse = thm "SComplex_inverse";
    val SComplex_divide = thm "SComplex_divide";
    val SComplex_minus = thm "SComplex_minus";
    val SComplex_minus_iff = thm "SComplex_minus_iff";
    val SComplex_diff = thm "SComplex_diff";
    val SComplex_add_cancel = thm "SComplex_add_cancel";
    val SReal_hcmod_hcomplex_of_complex = thm "SReal_hcmod_hcomplex_of_complex";
    val SReal_hcmod_number_of = thm "SReal_hcmod_number_of";
    val SReal_hcmod_SComplex = thm "SReal_hcmod_SComplex";
    val SComplex_hcomplex_of_complex = thm "SComplex_hcomplex_of_complex";
    val SComplex_number_of = thm "SComplex_number_of";
    val SComplex_divide_number_of = thm "SComplex_divide_number_of";
    val SComplex_UNIV_complex = thm "SComplex_UNIV_complex";
    val SComplex_iff = thm "SComplex_iff";
    val hcomplex_of_complex_image = thm "hcomplex_of_complex_image";
    val inv_hcomplex_of_complex_image = thm "inv_hcomplex_of_complex_image";
    val SComplex_hcomplex_of_complex_image = thm "SComplex_hcomplex_of_complex_image";
    val SComplex_SReal_dense = thm "SComplex_SReal_dense";
    val SComplex_hcmod_SReal = thm "SComplex_hcmod_SReal";
    val SComplex_zero = thm "SComplex_zero";
    val SComplex_one = thm "SComplex_one";
    val CFinite_add = thm "CFinite_add";
    val CFinite_mult = thm "CFinite_mult";
    val CFinite_minus_iff = thm "CFinite_minus_iff";
    val SComplex_subset_CFinite = thm "SComplex_subset_CFinite";
    val HFinite_hcmod_hcomplex_of_complex = thm "HFinite_hcmod_hcomplex_of_complex";
    val CFinite_hcomplex_of_complex = thm "CFinite_hcomplex_of_complex";
    val CFiniteD = thm "CFiniteD";
    val CFinite_hcmod_iff = thm "CFinite_hcmod_iff";
    val CFinite_number_of = thm "CFinite_number_of";
    val CFinite_bounded = thm "CFinite_bounded";
    val CInfinitesimal_zero = thm "CInfinitesimal_zero";
    val hcomplex_sum_of_halves = thm "hcomplex_sum_of_halves";
    val CInfinitesimal_hcmod_iff = thm "CInfinitesimal_hcmod_iff";
    val one_not_CInfinitesimal = thm "one_not_CInfinitesimal";
    val CInfinitesimal_add = thm "CInfinitesimal_add";
    val CInfinitesimal_minus_iff = thm "CInfinitesimal_minus_iff";
    val CInfinitesimal_diff = thm "CInfinitesimal_diff";
    val CInfinitesimal_mult = thm "CInfinitesimal_mult";
    val CInfinitesimal_CFinite_mult = thm "CInfinitesimal_CFinite_mult";
    val CInfinitesimal_CFinite_mult2 = thm "CInfinitesimal_CFinite_mult2";
    val CInfinite_hcmod_iff = thm "CInfinite_hcmod_iff";
    val CInfinite_inverse_CInfinitesimal = thm "CInfinite_inverse_CInfinitesimal";
    val CInfinite_mult = thm "CInfinite_mult";
    val CInfinite_minus_iff = thm "CInfinite_minus_iff";
    val CFinite_sum_squares = thm "CFinite_sum_squares";
    val not_CInfinitesimal_not_zero = thm "not_CInfinitesimal_not_zero";
    val not_CInfinitesimal_not_zero2 = thm "not_CInfinitesimal_not_zero2";
    val CFinite_diff_CInfinitesimal_hcmod = thm "CFinite_diff_CInfinitesimal_hcmod";
    val hcmod_less_CInfinitesimal = thm "hcmod_less_CInfinitesimal";
    val hcmod_le_CInfinitesimal = thm "hcmod_le_CInfinitesimal";
    val CInfinitesimal_interval = thm "CInfinitesimal_interval";
    val CInfinitesimal_interval2 = thm "CInfinitesimal_interval2";
    val not_CInfinitesimal_mult = thm "not_CInfinitesimal_mult";
    val CInfinitesimal_mult_disj = thm "CInfinitesimal_mult_disj";
    val CFinite_CInfinitesimal_diff_mult = thm "CFinite_CInfinitesimal_diff_mult";
    val CInfinitesimal_subset_CFinite = thm "CInfinitesimal_subset_CFinite";
    val CInfinitesimal_hcomplex_of_complex_mult = thm "CInfinitesimal_hcomplex_of_complex_mult";
    val CInfinitesimal_hcomplex_of_complex_mult2 = thm "CInfinitesimal_hcomplex_of_complex_mult2";
    val mem_cinfmal_iff = thm "mem_cinfmal_iff";
    val capprox_minus_iff = thm "capprox_minus_iff";
    val capprox_minus_iff2 = thm "capprox_minus_iff2";
    val capprox_refl = thm "capprox_refl";
    val capprox_sym = thm "capprox_sym";
    val capprox_trans = thm "capprox_trans";
    val capprox_trans2 = thm "capprox_trans2";
    val capprox_trans3 = thm "capprox_trans3";
    val number_of_capprox_reorient = thm "number_of_capprox_reorient";
    val CInfinitesimal_capprox_minus = thm "CInfinitesimal_capprox_minus";
    val capprox_monad_iff = thm "capprox_monad_iff";
    val Infinitesimal_capprox = thm "Infinitesimal_capprox";
    val capprox_add = thm "capprox_add";
    val capprox_minus = thm "capprox_minus";
    val capprox_minus2 = thm "capprox_minus2";
    val capprox_minus_cancel = thm "capprox_minus_cancel";
    val capprox_add_minus = thm "capprox_add_minus";
    val capprox_mult1 = thm "capprox_mult1";
    val capprox_mult2 = thm "capprox_mult2";
    val capprox_mult_subst = thm "capprox_mult_subst";
    val capprox_mult_subst2 = thm "capprox_mult_subst2";
    val capprox_mult_subst_SComplex = thm "capprox_mult_subst_SComplex";
    val capprox_eq_imp = thm "capprox_eq_imp";
    val CInfinitesimal_minus_capprox = thm "CInfinitesimal_minus_capprox";
    val bex_CInfinitesimal_iff = thm "bex_CInfinitesimal_iff";
    val bex_CInfinitesimal_iff2 = thm "bex_CInfinitesimal_iff2";
    val CInfinitesimal_add_capprox = thm "CInfinitesimal_add_capprox";
    val CInfinitesimal_add_capprox_self = thm "CInfinitesimal_add_capprox_self";
    val CInfinitesimal_add_capprox_self2 = thm "CInfinitesimal_add_capprox_self2";
    val CInfinitesimal_add_minus_capprox_self = thm "CInfinitesimal_add_minus_capprox_self";
    val CInfinitesimal_add_cancel = thm "CInfinitesimal_add_cancel";
    val CInfinitesimal_add_right_cancel = thm "CInfinitesimal_add_right_cancel";
    val capprox_add_left_cancel = thm "capprox_add_left_cancel";
    val capprox_add_right_cancel = thm "capprox_add_right_cancel";
    val capprox_add_mono1 = thm "capprox_add_mono1";
    val capprox_add_mono2 = thm "capprox_add_mono2";
    val capprox_add_left_iff = thm "capprox_add_left_iff";
    val capprox_add_right_iff = thm "capprox_add_right_iff";
    val capprox_CFinite = thm "capprox_CFinite";
    val capprox_hcomplex_of_complex_CFinite = thm "capprox_hcomplex_of_complex_CFinite";
    val capprox_mult_CFinite = thm "capprox_mult_CFinite";
    val capprox_mult_hcomplex_of_complex = thm "capprox_mult_hcomplex_of_complex";
    val capprox_SComplex_mult_cancel_zero = thm "capprox_SComplex_mult_cancel_zero";
    val capprox_mult_SComplex1 = thm "capprox_mult_SComplex1";
    val capprox_mult_SComplex2 = thm "capprox_mult_SComplex2";
    val capprox_mult_SComplex_zero_cancel_iff = thm "capprox_mult_SComplex_zero_cancel_iff";
    val capprox_SComplex_mult_cancel = thm "capprox_SComplex_mult_cancel";
    val capprox_SComplex_mult_cancel_iff1 = thm "capprox_SComplex_mult_cancel_iff1";
    val capprox_hcmod_approx_zero = thm "capprox_hcmod_approx_zero";
    val capprox_approx_zero_iff = thm "capprox_approx_zero_iff";
    val capprox_minus_zero_cancel_iff = thm "capprox_minus_zero_cancel_iff";
    val Infinitesimal_hcmod_add_diff = thm "Infinitesimal_hcmod_add_diff";
    val approx_hcmod_add_hcmod = thm "approx_hcmod_add_hcmod";
    val capprox_hcmod_approx = thm "capprox_hcmod_approx";
    val CInfinitesimal_less_SComplex = thm "CInfinitesimal_less_SComplex";
    val SComplex_Int_CInfinitesimal_zero = thm "SComplex_Int_CInfinitesimal_zero";
    val SComplex_CInfinitesimal_zero = thm "SComplex_CInfinitesimal_zero";
    val SComplex_CFinite_diff_CInfinitesimal = thm "SComplex_CFinite_diff_CInfinitesimal";
    val hcomplex_of_complex_CFinite_diff_CInfinitesimal = thm "hcomplex_of_complex_CFinite_diff_CInfinitesimal";
    val hcomplex_of_complex_CInfinitesimal_iff_0 = thm "hcomplex_of_complex_CInfinitesimal_iff_0";
    val number_of_not_CInfinitesimal = thm "number_of_not_CInfinitesimal";
    val capprox_SComplex_not_zero = thm "capprox_SComplex_not_zero";
    val CFinite_diff_CInfinitesimal_capprox = thm "CFinite_diff_CInfinitesimal_capprox";
    val CInfinitesimal_ratio = thm "CInfinitesimal_ratio";
    val SComplex_capprox_iff = thm "SComplex_capprox_iff";
    val number_of_capprox_iff = thm "number_of_capprox_iff";
    val number_of_CInfinitesimal_iff = thm "number_of_CInfinitesimal_iff";
    val hcomplex_of_complex_approx_iff = thm "hcomplex_of_complex_approx_iff";
    val hcomplex_of_complex_capprox_number_of_iff = thm "hcomplex_of_complex_capprox_number_of_iff";
    val capprox_unique_complex = thm "capprox_unique_complex";
    val hcomplex_capproxD1 = thm "hcomplex_capproxD1";
    val hcomplex_capproxD2 = thm "hcomplex_capproxD2";
    val hcomplex_capproxI = thm "hcomplex_capproxI";
    val capprox_approx_iff = thm "capprox_approx_iff";
    val hcomplex_of_hypreal_capprox_iff = thm "hcomplex_of_hypreal_capprox_iff";
    val CFinite_HFinite_Re = thm "CFinite_HFinite_Re";
    val CFinite_HFinite_Im = thm "CFinite_HFinite_Im";
    val HFinite_Re_Im_CFinite = thm "HFinite_Re_Im_CFinite";
    val CFinite_HFinite_iff = thm "CFinite_HFinite_iff";
    val SComplex_Re_SReal = thm "SComplex_Re_SReal";
    val SComplex_Im_SReal = thm "SComplex_Im_SReal";
    val Reals_Re_Im_SComplex = thm "Reals_Re_Im_SComplex";
    val SComplex_SReal_iff = thm "SComplex_SReal_iff";
    val CInfinitesimal_Infinitesimal_iff = thm "CInfinitesimal_Infinitesimal_iff";
    val eq_Abs_star_Bex = thm "eq_Abs_star_Bex";
    val stc_part_Ex = thm "stc_part_Ex";
    val stc_part_Ex1 = thm "stc_part_Ex1";
    val CFinite_Int_CInfinite_empty = thm "CFinite_Int_CInfinite_empty";
    val CFinite_not_CInfinite = thm "CFinite_not_CInfinite";
    val not_CFinite_CInfinite = thm "not_CFinite_CInfinite";
    val CInfinite_CFinite_disj = thm "CInfinite_CFinite_disj";
    val CInfinite_CFinite_iff = thm "CInfinite_CFinite_iff";
    val CFinite_CInfinite_iff = thm "CFinite_CInfinite_iff";
    val CInfinite_diff_CFinite_CInfinitesimal_disj = thm "CInfinite_diff_CFinite_CInfinitesimal_disj";
    val CFinite_inverse = thm "CFinite_inverse";
    val CFinite_inverse2 = thm "CFinite_inverse2";
    val CInfinitesimal_inverse_CFinite = thm "CInfinitesimal_inverse_CFinite";
    val CFinite_not_CInfinitesimal_inverse = thm "CFinite_not_CInfinitesimal_inverse";
    val capprox_inverse = thm "capprox_inverse";
    val hcomplex_of_complex_capprox_inverse = thms "hcomplex_of_complex_capprox_inverse";
    val inverse_add_CInfinitesimal_capprox = thm "inverse_add_CInfinitesimal_capprox";
    val inverse_add_CInfinitesimal_capprox2 = thm "inverse_add_CInfinitesimal_capprox2";
    val inverse_add_CInfinitesimal_approx_CInfinitesimal = thm "inverse_add_CInfinitesimal_approx_CInfinitesimal";
    val CInfinitesimal_square_iff = thm "CInfinitesimal_square_iff";
    val capprox_CFinite_mult_cancel = thm "capprox_CFinite_mult_cancel";
    val capprox_CFinite_mult_cancel_iff1 = thm "capprox_CFinite_mult_cancel_iff1";
    val capprox_cmonad_iff = thm "capprox_cmonad_iff";
    val CInfinitesimal_cmonad_eq = thm "CInfinitesimal_cmonad_eq";
    val mem_cmonad_iff = thm "mem_cmonad_iff";
    val CInfinitesimal_cmonad_zero_iff = thm "CInfinitesimal_cmonad_zero_iff";
    val cmonad_zero_minus_iff = thm "cmonad_zero_minus_iff";
    val cmonad_zero_hcmod_iff = thm "cmonad_zero_hcmod_iff";
    val mem_cmonad_self = thm "mem_cmonad_self";
    val stc_capprox_self = thm "stc_capprox_self";
    val stc_SComplex = thm "stc_SComplex";
    val stc_CFinite = thm "stc_CFinite";
    val stc_SComplex_eq = thm "stc_SComplex_eq";
    val stc_hcomplex_of_complex = thm "stc_hcomplex_of_complex";
    val stc_eq_capprox = thm "stc_eq_capprox";
    val capprox_stc_eq = thm "capprox_stc_eq";
    val stc_eq_capprox_iff = thm "stc_eq_capprox_iff";
    val stc_CInfinitesimal_add_SComplex = thm "stc_CInfinitesimal_add_SComplex";
    val stc_CInfinitesimal_add_SComplex2 = thm "stc_CInfinitesimal_add_SComplex2";
    val CFinite_stc_CInfinitesimal_add = thm "CFinite_stc_CInfinitesimal_add";
    val stc_add = thm "stc_add";
    val stc_number_of = thm "stc_number_of";
    val stc_zero = thm "stc_zero";
    val stc_one = thm "stc_one";
    val stc_minus = thm "stc_minus";
    val stc_diff = thm "stc_diff";
    val lemma_stc_mult = thm "lemma_stc_mult";
    val stc_mult = thm "stc_mult";
    val stc_CInfinitesimal = thm "stc_CInfinitesimal";
    val stc_not_CInfinitesimal = thm "stc_not_CInfinitesimal";
    val stc_inverse = thm "stc_inverse";
    val stc_divide = thm "stc_divide";
    val stc_idempotent = thm "stc_idempotent";
    val CFinite_HFinite_hcomplex_of_hypreal = thm "CFinite_HFinite_hcomplex_of_hypreal";
    val SComplex_SReal_hcomplex_of_hypreal = thm "SComplex_SReal_hcomplex_of_hypreal";
    val stc_hcomplex_of_hypreal = thm "stc_hcomplex_of_hypreal";
    val CInfinitesimal_hcnj_iff = thm "CInfinitesimal_hcnj_iff";
    val CInfinite_HInfinite_iff = thm "CInfinite_HInfinite_iff";
    val hcomplex_split_CInfinitesimal_iff = thm "hcomplex_split_CInfinitesimal_iff";
    val hcomplex_split_CFinite_iff = thm "hcomplex_split_CFinite_iff";
    val hcomplex_split_SComplex_iff = thm "hcomplex_split_SComplex_iff";
    val hcomplex_split_CInfinite_iff = thm "hcomplex_split_CInfinite_iff";
    val hcomplex_split_capprox_iff = thm "hcomplex_split_capprox_iff";
    val complex_seq_to_hcomplex_CInfinitesimal = thm "complex_seq_to_hcomplex_CInfinitesimal";
    val CInfinitesimal_hcomplex_of_hypreal_epsilon = thm "CInfinitesimal_hcomplex_of_hypreal_epsilon";
    val hcomplex_of_complex_approx_zero_iff = thm "hcomplex_of_complex_approx_zero_iff";
    val hcomplex_of_complex_approx_zero_iff2 = thm "hcomplex_of_complex_approx_zero_iff2";
    *}

    end

### Closure Laws for SComplex, the Standard Complex Numbers

lemma SComplex_add:

      [| x ∈ SComplex; y ∈ SComplex |] ==> x + y ∈ SComplex

lemma SComplex_mult:

      [| x ∈ SComplex; y ∈ SComplex |] ==> x * y ∈ SComplex

lemma SComplex_inverse:

      x ∈ SComplex ==> inverse x ∈ SComplex

lemma SComplex_divide:

      [| x ∈ SComplex; y ∈ SComplex |] ==> x / y ∈ SComplex

lemma SComplex_minus:

      x ∈ SComplex ==> - x ∈ SComplex

lemma SComplex_minus_iff:

      (- x ∈ SComplex) = (x ∈ SComplex)

lemma SComplex_diff:

      [| x ∈ SComplex; y ∈ SComplex |] ==> x - y ∈ SComplex

lemma SComplex_add_cancel:

      [| x + y ∈ SComplex; y ∈ SComplex |] ==> x ∈ SComplex

lemma SReal_hcmod_hcomplex_of_complex:

      hcmod (star_of r) ∈ Reals

lemma SReal_hcmod_number_of:

      hcmod (number_of w) ∈ Reals

lemma SReal_hcmod_SComplex:

      x ∈ SComplex ==> hcmod x ∈ Reals

lemma SComplex_hcomplex_of_complex:

      star_of x ∈ SComplex

lemma SComplex_number_of:

      number_of w ∈ SComplex

lemma SComplex_divide_number_of:

      r ∈ SComplex ==> r / number_of w ∈ SComplex

lemma SComplex_UNIV_complex:

      {x. star_of x ∈ SComplex} = UNIV

lemma SComplex_iff:

      (x ∈ SComplex) = (∃y. x = star_of y)

lemma hcomplex_of_complex_image:

      range star_of = SComplex

lemma inv_hcomplex_of_complex_image:

      inv star_of ` SComplex = UNIV

lemma SComplex_hcomplex_of_complex_image:

      [| ∃x. x ∈ P; P ⊆ SComplex |] ==> ∃Q. P = star_of ` Q

lemma SComplex_SReal_dense:

      [| x ∈ SComplex; y ∈ SComplex; hcmod x < hcmod y |]
      ==> ∃r∈Reals. hcmod x < r ∧ r < hcmod y

lemma SComplex_hcmod_SReal:

      z ∈ SComplex ==> hcmod z ∈ Reals

lemma SComplex_zero:

      0 ∈ SComplex

lemma SComplex_one:

      1 ∈ SComplex

### The Finite Elements form a Subring

lemma CFinite_add:

      [| x ∈ CFinite; y ∈ CFinite |] ==> x + y ∈ CFinite

lemma CFinite_mult:

      [| x ∈ CFinite; y ∈ CFinite |] ==> x * y ∈ CFinite

lemma CFinite_minus_iff:

      (- x ∈ CFinite) = (x ∈ CFinite)

lemma SComplex_subset_CFinite:

      SComplex ⊆ CFinite

lemma HFinite_hcmod_hcomplex_of_complex:

      hcmod (star_of r) ∈ HFinite

lemma CFinite_hcomplex_of_complex:

      star_of x ∈ CFinite

lemma CFiniteD:

      x ∈ CFinite ==> ∃t∈Reals. hcmod x < t

lemma CFinite_hcmod_iff:

      (x ∈ CFinite) = (hcmod x ∈ HFinite)

lemma CFinite_number_of:

      number_of w ∈ CFinite

lemma CFinite_bounded:

      [| x ∈ CFinite; y ≤ hcmod x; 0 ≤ y |] ==> y ∈ HFinite

### The Complex Infinitesimals form a Subring

lemma CInfinitesimal_zero:

      0 ∈ CInfinitesimal

lemma hcomplex_sum_of_halves:

      x / 2 + x / 2 = x

lemma CInfinitesimal_hcmod_iff:

      (z ∈ CInfinitesimal) = (hcmod z ∈ Infinitesimal)

lemma one_not_CInfinitesimal:

      1 ∉ CInfinitesimal

lemma CInfinitesimal_add:

      [| x ∈ CInfinitesimal; y ∈ CInfinitesimal |] ==> x + y ∈ CInfinitesimal

lemma CInfinitesimal_minus_iff:

      (- x ∈ CInfinitesimal) = (x ∈ CInfinitesimal)

lemma CInfinitesimal_diff:

      [| x ∈ CInfinitesimal; y ∈ CInfinitesimal |] ==> x - y ∈ CInfinitesimal

lemma CInfinitesimal_mult:

      [| x ∈ CInfinitesimal; y ∈ CInfinitesimal |] ==> x * y ∈ CInfinitesimal

lemma CInfinitesimal_CFinite_mult:

      [| x ∈ CInfinitesimal; y ∈ CFinite |] ==> x * y ∈ CInfinitesimal

lemma CInfinitesimal_CFinite_mult2:

      [| x ∈ CInfinitesimal; y ∈ CFinite |] ==> y * x ∈ CInfinitesimal

lemma CInfinite_hcmod_iff:

      (z ∈ CInfinite) = (hcmod z ∈ HInfinite)

lemma CInfinite_inverse_CInfinitesimal:

      x ∈ CInfinite ==> inverse x ∈ CInfinitesimal

lemma CInfinite_mult:

      [| x ∈ CInfinite; y ∈ CInfinite |] ==> x * y ∈ CInfinite

lemma CInfinite_minus_iff:

      (- x ∈ CInfinite) = (x ∈ CInfinite)

lemma CFinite_sum_squares:

      [| a ∈ CFinite; b ∈ CFinite; c ∈ CFinite |] ==> a * a + b * b + c * c ∈ CFinite

lemma not_CInfinitesimal_not_zero:

      x ∉ CInfinitesimal ==> x ≠ 0

lemma not_CInfinitesimal_not_zero2:

      x ∈ CFinite - CInfinitesimal ==> x ≠ 0

lemma CFinite_diff_CInfinitesimal_hcmod:

      x ∈ CFinite - CInfinitesimal ==> hcmod x ∈ HFinite - Infinitesimal

lemma hcmod_less_CInfinitesimal:

      [| e ∈ CInfinitesimal; hcmod x < hcmod e |] ==> x ∈ CInfinitesimal

lemma hcmod_le_CInfinitesimal:

      [| e ∈ CInfinitesimal; hcmod x ≤ hcmod e |] ==> x ∈ CInfinitesimal

lemma CInfinitesimal_interval:

      [| e ∈ CInfinitesimal; e' ∈ CInfinitesimal; hcmod e' < hcmod x;
         hcmod x < hcmod e |]
      ==> x ∈ CInfinitesimal

lemma CInfinitesimal_interval2:

      [| e ∈ CInfinitesimal; e' ∈ CInfinitesimal; hcmod e' ≤ hcmod x;
         hcmod x ≤ hcmod e |]
      ==> x ∈ CInfinitesimal

lemma not_CInfinitesimal_mult:

      [| x ∉ CInfinitesimal; y ∉ CInfinitesimal |] ==> x * y ∉ CInfinitesimal

lemma CInfinitesimal_mult_disj:

      x * y ∈ CInfinitesimal ==> x ∈ CInfinitesimal ∨ y ∈ CInfinitesimal

lemma CFinite_CInfinitesimal_diff_mult:

      [| x ∈ CFinite - CInfinitesimal; y ∈ CFinite - CInfinitesimal |]
      ==> x * y ∈ CFinite - CInfinitesimal

lemma CInfinitesimal_subset_CFinite:

      CInfinitesimal ⊆ CFinite

lemma CInfinitesimal_hcomplex_of_complex_mult:

      x ∈ CInfinitesimal ==> x * star_of r ∈ CInfinitesimal

lemma CInfinitesimal_hcomplex_of_complex_mult2:

      x ∈ CInfinitesimal ==> star_of r * x ∈ CInfinitesimal

### The ``Infinitely Close'' Relation

lemma mem_cinfmal_iff:

      (x ∈ CInfinitesimal) = (x @c= 0)

lemma capprox_minus_iff:

      (x @c= y) = (x + - y @c= 0)

lemma capprox_minus_iff2:

      (x @c= y) = (- y + x @c= 0)

lemma capprox_refl:

      x @c= x

lemma capprox_sym:

      x @c= y ==> y @c= x

lemma capprox_trans:

      [| x @c= y; y @c= z |] ==> x @c= z

lemma capprox_trans2:

      [| r @c= x; s @c= x |] ==> r @c= s

lemma capprox_trans3:

      [| x @c= r; x @c= s |] ==> r @c= s

lemma number_of_capprox_reorient:

      (number_of w @c= x) = (x @c= number_of w)

lemma CInfinitesimal_capprox_minus:

      (x - y ∈ CInfinitesimal) = (x @c= y)

lemma capprox_monad_iff:

      (x @c= y) = (cmonad x = cmonad y)

lemma Infinitesimal_capprox:

      [| x ∈ CInfinitesimal; y ∈ CInfinitesimal |] ==> x @c= y

lemma capprox_add:

      [| a @c= b; c @c= d |] ==> a + c @c= b + d

lemma capprox_minus:

      a @c= b ==> - a @c= - b

lemma capprox_minus2:

      - a @c= - b ==> a @c= b

lemma capprox_minus_cancel:

      (- a @c= - b) = (a @c= b)

lemma capprox_add_minus:

      [| a @c= b; c @c= d |] ==> a + - c @c= b + - d

lemma capprox_mult1:

      [| a @c= b; c ∈ CFinite |] ==> a * c @c= b * c

lemma capprox_mult2:

      [| a @c= b; c ∈ CFinite |] ==> c * a @c= c * b

lemma capprox_mult_subst:

      [| u @c= v * x; x @c= y; v ∈ CFinite |] ==> u @c= v * y

lemma capprox_mult_subst2:

      [| u @c= x * v; x @c= y; v ∈ CFinite |] ==> u @c= y * v

lemma capprox_mult_subst_SComplex:

      [| u @c= x * star_of v; x @c= y |] ==> u @c= y * star_of v

lemma capprox_eq_imp:

      a = b ==> a @c= b

lemma CInfinitesimal_minus_capprox:

      x ∈ CInfinitesimal ==> - x @c= x

lemma bex_CInfinitesimal_iff:

      (∃y∈CInfinitesimal. x - z = y) = (x @c= z)

lemma bex_CInfinitesimal_iff2:

      (∃y∈CInfinitesimal. x = z + y) = (x @c= z)

lemma CInfinitesimal_add_capprox:

      [| y ∈ CInfinitesimal; x + y = z |] ==> x @c= z

lemma CInfinitesimal_add_capprox_self:

      y ∈ CInfinitesimal ==> x @c= x + y

lemma CInfinitesimal_add_capprox_self2:

      y ∈ CInfinitesimal ==> x @c= y + x

lemma CInfinitesimal_add_minus_capprox_self:

      y ∈ CInfinitesimal ==> x @c= x + - y

lemma CInfinitesimal_add_cancel:

      [| y ∈ CInfinitesimal; x + y @c= z |] ==> x @c= z

lemma CInfinitesimal_add_right_cancel:

      [| y ∈ CInfinitesimal; x @c= z + y |] ==> x @c= z

lemma capprox_add_left_cancel:

      d + b @c= d + c ==> b @c= c

lemma capprox_add_right_cancel:

      b + d @c= c + d ==> b @c= c

lemma capprox_add_mono1:

      b @c= c ==> d + b @c= d + c

lemma capprox_add_mono2:

      b @c= c ==> b + a @c= c + a

lemma capprox_add_left_iff:

      (a + b @c= a + c) = (b @c= c)

lemma capprox_add_right_iff:

      (b + a @c= c + a) = (b @c= c)

lemma capprox_CFinite:

      [| x ∈ CFinite; x @c= y |] ==> y ∈ CFinite

lemma capprox_hcomplex_of_complex_CFinite:

      x @c= star_of D ==> x ∈ CFinite

lemma capprox_mult_CFinite:

      [| a @c= b; c @c= d; b ∈ CFinite; d ∈ CFinite |] ==> a * c @c= b * d

lemma capprox_mult_hcomplex_of_complex:

      [| a @c= star_of b; c @c= star_of d |] ==> a * c @c= star_of b * star_of d

lemma capprox_SComplex_mult_cancel_zero:

      [| a ∈ SComplex; a ≠ 0; a * x @c= 0 |] ==> x @c= 0

lemma capprox_mult_SComplex1:

      [| a ∈ SComplex; x @c= 0 |] ==> x * a @c= 0

lemma capprox_mult_SComplex2:

      [| a ∈ SComplex; x @c= 0 |] ==> a * x @c= 0

lemma capprox_mult_SComplex_zero_cancel_iff:

      [| a ∈ SComplex; a ≠ 0 |] ==> (a * x @c= 0) = (x @c= 0)

lemma capprox_SComplex_mult_cancel:

      [| a ∈ SComplex; a ≠ 0; a * w @c= a * z |] ==> w @c= z

lemma capprox_SComplex_mult_cancel_iff1:

      [| a ∈ SComplex; a ≠ 0 |] ==> (a * w @c= a * z) = (w @c= z)

lemma capprox_hcmod_approx_zero:

      (x @c= y) = (hcmod (y - x) ≈ 0)

lemma capprox_approx_zero_iff:

      (x @c= 0) = (hcmod x ≈ 0)

lemma capprox_minus_zero_cancel_iff:

      (- x @c= 0) = (x @c= 0)

lemma Infinitesimal_hcmod_add_diff:

      u @c= 0 ==> hcmod (x + u) - hcmod x ∈ Infinitesimal

lemma approx_hcmod_add_hcmod:

      u @c= 0 ==> hcmod (x + u) ≈ hcmod x

lemma capprox_hcmod_approx:

      x @c= y ==> hcmod x ≈ hcmod y

### Zero is the Only Infinitesimal Complex Number

lemma CInfinitesimal_less_SComplex:

      [| x ∈ SComplex; y ∈ CInfinitesimal; 0 < hcmod x |] ==> hcmod y < hcmod x

lemma SComplex_Int_CInfinitesimal_zero:

      SComplex ∩ CInfinitesimal = {0}

lemma SComplex_CInfinitesimal_zero:

      [| x ∈ SComplex; x ∈ CInfinitesimal |] ==> x = 0

lemma SComplex_CFinite_diff_CInfinitesimal:

      [| x ∈ SComplex; x ≠ 0 |] ==> x ∈ CFinite - CInfinitesimal

lemma hcomplex_of_complex_CFinite_diff_CInfinitesimal:

      star_of x ≠ 0 ==> star_of x ∈ CFinite - CInfinitesimal

lemma hcomplex_of_complex_CInfinitesimal_iff_0:

      (star_of x ∈ CInfinitesimal) = (x = 0)

lemma number_of_not_CInfinitesimal:

      number_of w ≠ 0 ==> number_of w ∉ CInfinitesimal

lemma capprox_SComplex_not_zero:

      [| y ∈ SComplex; x @c= y; y ≠ 0 |] ==> x ≠ 0

lemma CFinite_diff_CInfinitesimal_capprox:

      [| x @c= y; y ∈ CFinite - CInfinitesimal |] ==> x ∈ CFinite - CInfinitesimal

lemma CInfinitesimal_ratio:

      [| y ≠ 0; y ∈ CInfinitesimal; x / y ∈ CFinite |] ==> x ∈ CInfinitesimal

lemma SComplex_capprox_iff:

      [| x ∈ SComplex; y ∈ SComplex |] ==> (x @c= y) = (x = y)

lemma number_of_capprox_iff:

      (number_of v @c= number_of w) = (number_of v = number_of w)

lemma number_of_CInfinitesimal_iff:

      (number_of w ∈ CInfinitesimal) = (number_of w = 0)

lemma hcomplex_of_complex_approx_iff:

      (star_of k @c= star_of m) = (k = m)

lemma hcomplex_of_complex_capprox_number_of_iff:

      (star_of k @c= number_of w) = (k = number_of w)

lemma capprox_unique_complex:

      [| r ∈ SComplex; s ∈ SComplex; r @c= x; s @c= x |] ==> r = s

lemma hcomplex_capproxD1:

      star_n X @c= star_n Y ==> star_n (%n. Re (X n)) ≈ star_n (%n. Re (Y n))

lemma hcomplex_capproxD2:

      star_n X @c= star_n Y ==> star_n (%n. Im (X n)) ≈ star_n (%n. Im (Y n))

lemma hcomplex_capproxI:

      [| star_n (%n. Re (X n)) ≈ star_n (%n. Re (Y n));
         star_n (%n. Im (X n)) ≈ star_n (%n. Im (Y n)) |]
      ==> star_n X @c= star_n Y

lemma capprox_approx_iff:

      (star_n X @c= star_n Y) =
      (star_n (%n. Re (X n)) ≈ star_n (%n. Re (Y n)) ∧
       star_n (%n. Im (X n)) ≈ star_n (%n. Im (Y n)))

lemma hcomplex_of_hypreal_capprox_iff:

      (hcomplex_of_hypreal x @c= hcomplex_of_hypreal z) = (x ≈ z)

lemma CFinite_HFinite_Re:

      star_n X ∈ CFinite ==> star_n (%n. Re (X n)) ∈ HFinite

lemma CFinite_HFinite_Im:

      star_n X ∈ CFinite ==> star_n (%n. Im (X n)) ∈ HFinite

lemma HFinite_Re_Im_CFinite:

      [| star_n (%n. Re (X n)) ∈ HFinite; star_n (%n. Im (X n)) ∈ HFinite |]
      ==> star_n X ∈ CFinite

lemma CFinite_HFinite_iff:

      (star_n X ∈ CFinite) =
      (star_n (%n. Re (X n)) ∈ HFinite ∧ star_n (%n. Im (X n)) ∈ HFinite)

lemma SComplex_Re_SReal:

      star_n X ∈ SComplex ==> star_n (%n. Re (X n)) ∈ Reals

lemma SComplex_Im_SReal:

      star_n X ∈ SComplex ==> star_n (%n. Im (X n)) ∈ Reals

lemma Reals_Re_Im_SComplex:

      [| star_n (%n. Re (X n)) ∈ Reals; star_n (%n. Im (X n)) ∈ Reals |]
      ==> star_n X ∈ SComplex

lemma SComplex_SReal_iff:

      (star_n X ∈ SComplex) =
      (star_n (%n. Re (X n)) ∈ Reals ∧ star_n (%n. Im (X n)) ∈ Reals)

lemma CInfinitesimal_Infinitesimal_iff:

      (star_n X ∈ CInfinitesimal) =
      (star_n (%n. Re (X n)) ∈ Infinitesimal ∧ star_n (%n. Im (X n)) ∈ Infinitesimal)

lemma eq_Abs_star_EX:

      (∃t. P t) = (∃X. P (star_n X))

lemma eq_Abs_star_Bex:

      (∃t∈A. P t) = (∃X. star_n X ∈ A ∧ P (star_n X))

lemma stc_part_Ex:

      x ∈ CFinite ==> ∃t∈SComplex. x @c= t

lemma stc_part_Ex1:

      x ∈ CFinite ==> ∃!t. t ∈ SComplex ∧ x @c= t

lemma CFinite_Int_CInfinite_empty:

      CFinite ∩ CInfinite = {}

lemma CFinite_not_CInfinite:

      x ∈ CFinite ==> x ∉ CInfinite

lemma not_CFinite_CInfinite:

      x ∉ CFinite ==> x ∈ CInfinite

lemma CInfinite_CFinite_disj:

      x ∈ CInfinite ∨ x ∈ CFinite

lemma CInfinite_CFinite_iff:

      (x ∈ CInfinite) = (x ∉ CFinite)

lemma CFinite_CInfinite_iff:

      (x ∈ CFinite) = (x ∉ CInfinite)

lemma CInfinite_diff_CFinite_CInfinitesimal_disj:

      x ∉ CInfinitesimal ==> x ∈ CInfinite ∨ x ∈ CFinite - CInfinitesimal

lemma CFinite_inverse:

      [| x ∈ CFinite; x ∉ CInfinitesimal |] ==> inverse x ∈ CFinite

lemma CFinite_inverse2:

      x ∈ CFinite - CInfinitesimal ==> inverse x ∈ CFinite

lemma CInfinitesimal_inverse_CFinite:

      x ∉ CInfinitesimal ==> inverse x ∈ CFinite

lemma CFinite_not_CInfinitesimal_inverse:

      x ∈ CFinite - CInfinitesimal ==> inverse x ∈ CFinite - CInfinitesimal

lemma capprox_inverse:

      [| x @c= y; y ∈ CFinite - CInfinitesimal |] ==> inverse x @c= inverse y

lemmas hcomplex_of_complex_capprox_inverse:

      [| x @c= star_of x1; star_of x1 ≠ 0 |] ==> inverse x @c= inverse (star_of x1)

lemmas hcomplex_of_complex_capprox_inverse:

      [| x @c= star_of x1; star_of x1 ≠ 0 |] ==> inverse x @c= inverse (star_of x1)

lemma inverse_add_CInfinitesimal_capprox:

      [| x ∈ CFinite - CInfinitesimal; h ∈ CInfinitesimal |]
      ==> inverse (x + h) @c= inverse x

lemma inverse_add_CInfinitesimal_capprox2:

      [| x ∈ CFinite - CInfinitesimal; h ∈ CInfinitesimal |]
      ==> inverse (h + x) @c= inverse x

lemma inverse_add_CInfinitesimal_approx_CInfinitesimal:

      [| x ∈ CFinite - CInfinitesimal; h ∈ CInfinitesimal |]
      ==> inverse (x + h) - inverse x @c= h

lemma CInfinitesimal_square_iff:

      (x * x ∈ CInfinitesimal) = (x ∈ CInfinitesimal)

lemma capprox_CFinite_mult_cancel:

      [| a ∈ CFinite - CInfinitesimal; a * w @c= a * z |] ==> w @c= z

lemma capprox_CFinite_mult_cancel_iff1:

      a ∈ CFinite - CInfinitesimal ==> (a * w @c= a * z) = (w @c= z)

### Theorems About Monads

lemma capprox_cmonad_iff:

      (x @c= y) = (cmonad x = cmonad y)

lemma CInfinitesimal_cmonad_eq:

      e ∈ CInfinitesimal ==> cmonad (x + e) = cmonad x

lemma mem_cmonad_iff:

      (u ∈ cmonad x) = (- u ∈ cmonad (- x))

lemma CInfinitesimal_cmonad_zero_iff:

      (x ∈ CInfinitesimal) = (x ∈ cmonad 0)

lemma cmonad_zero_minus_iff:

      (x ∈ cmonad 0) = (- x ∈ cmonad 0)

lemma cmonad_zero_hcmod_iff:

      (x ∈ cmonad 0) = (hcmod x ∈ monad 0)

lemma mem_cmonad_self:

      x ∈ cmonad x

### Theorems About Standard Part

lemma stc_capprox_self:

      x ∈ CFinite ==> stc x @c= x

lemma stc_SComplex:

      x ∈ CFinite ==> stc x ∈ SComplex

lemma stc_CFinite:

      x ∈ CFinite ==> stc x ∈ CFinite

lemma stc_SComplex_eq:

      x ∈ SComplex ==> stc x = x

lemma stc_hcomplex_of_complex:

      stc (star_of x) = star_of x

lemma stc_eq_capprox:

      [| x ∈ CFinite; y ∈ CFinite; stc x = stc y |] ==> x @c= y

lemma capprox_stc_eq:

      [| x ∈ CFinite; y ∈ CFinite; x @c= y |] ==> stc x = stc y

lemma stc_eq_capprox_iff:

      [| x ∈ CFinite; y ∈ CFinite |] ==> (x @c= y) = (stc x = stc y)

lemma stc_CInfinitesimal_add_SComplex:

      [| x ∈ SComplex; e ∈ CInfinitesimal |] ==> stc (x + e) = x

lemma stc_CInfinitesimal_add_SComplex2:

      [| x ∈ SComplex; e ∈ CInfinitesimal |] ==> stc (e + x) = x

lemma CFinite_stc_CInfinitesimal_add:

      x ∈ CFinite ==> ∃e∈CInfinitesimal. x = stc x + e

lemma stc_add:

      [| x ∈ CFinite; y ∈ CFinite |] ==> stc (x + y) = stc x + stc y

lemma stc_number_of:

      stc (number_of w) = number_of w

lemma stc_zero:

      stc 0 = 0

lemma stc_one:

      stc 1 = 1

lemma stc_minus:

      y ∈ CFinite ==> stc (- y) = - stc y

lemma stc_diff:

      [| x ∈ CFinite; y ∈ CFinite |] ==> stc (x - y) = stc x - stc y

lemma lemma_stc_mult:

      [| x ∈ CFinite; y ∈ CFinite; e ∈ CInfinitesimal; ea ∈ CInfinitesimal |]
      ==> e * y + x * ea + e * ea ∈ CInfinitesimal

lemma stc_mult:

      [| x ∈ CFinite; y ∈ CFinite |] ==> stc (x * y) = stc x * stc y

lemma stc_CInfinitesimal:

      x ∈ CInfinitesimal ==> stc x = 0

lemma stc_not_CInfinitesimal:

      stc x ≠ 0 ==> x ∉ CInfinitesimal

lemma stc_inverse:

      [| x ∈ CFinite; stc x ≠ 0 |] ==> stc (inverse x) = inverse (stc x)

lemma stc_divide:

      [| x ∈ CFinite; y ∈ CFinite; stc y ≠ 0 |] ==> stc (x / y) = stc x / stc y

lemma stc_idempotent:

      x ∈ CFinite ==> stc (stc x) = stc x

lemma CFinite_HFinite_hcomplex_of_hypreal:

      z ∈ HFinite ==> hcomplex_of_hypreal z ∈ CFinite

lemma SComplex_SReal_hcomplex_of_hypreal:

      x ∈ Reals ==> hcomplex_of_hypreal x ∈ SComplex

lemma stc_hcomplex_of_hypreal:

      z ∈ HFinite ==> stc (hcomplex_of_hypreal z) = hcomplex_of_hypreal (st z)

lemma CInfinitesimal_hcnj_iff:

      (hcnj z ∈ CInfinitesimal) = (z ∈ CInfinitesimal)

lemma CInfinite_HInfinite_iff:

      (star_n X ∈ CInfinite) =
      (star_n (%n. Re (X n)) ∈ HInfinite ∨ star_n (%n. Im (X n)) ∈ HInfinite)

lemma hcomplex_split_CInfinitesimal_iff:

      (hcomplex_of_hypreal x + iii * hcomplex_of_hypreal y ∈ CInfinitesimal) =
      (x ∈ Infinitesimal ∧ y ∈ Infinitesimal)

lemma hcomplex_split_CFinite_iff:

      (hcomplex_of_hypreal x + iii * hcomplex_of_hypreal y ∈ CFinite) =
      (x ∈ HFinite ∧ y ∈ HFinite)

lemma hcomplex_split_SComplex_iff:

      (hcomplex_of_hypreal x + iii * hcomplex_of_hypreal y ∈ SComplex) =
      (x ∈ Reals ∧ y ∈ Reals)

lemma hcomplex_split_CInfinite_iff:

      (hcomplex_of_hypreal x + iii * hcomplex_of_hypreal y ∈ CInfinite) =
      (x ∈ HInfinite ∨ y ∈ HInfinite)

lemma hcomplex_split_capprox_iff:

      (hcomplex_of_hypreal x + iii * hcomplex_of_hypreal y @c=
       hcomplex_of_hypreal x' + iii * hcomplex_of_hypreal y') =
      (x ≈ x' ∧ y ≈ y')

lemma complex_seq_to_hcomplex_CInfinitesimal:

      ∀n. cmod (X n - x) < inverse (real (Suc n))
      ==> star_n X - star_of x ∈ CInfinitesimal

lemma CInfinitesimal_hcomplex_of_hypreal_epsilon:

      hcomplex_of_hypreal ε ∈ CInfinitesimal

lemma hcomplex_of_complex_approx_zero_iff:

      (star_of z @c= 0) = (z = 0)

lemma hcomplex_of_complex_approx_zero_iff2:

      (0 @c= star_of z) = (z = 0)