`uc'
----

uc()
     :: Create a new indeterminate for an undermined coeficient.

RETURN
     indeterminate with its `vtype' 1.

   * At every evaluation of command `uc()', a new indeterminate in the
     sequence of indeterminates `_0', `_1', `_2', ...  is created
     successively.

   * Indeterminates created by `uc()' cannot be input on the keyboard.
     By this property, you are free, no matter how many indeterminates
     you will create dynamically by a program, from collision of
     created names with indeterminates input from the keyboard or from
     program files.

   * Functions, `rtostr()' and `strtov()', are used to create ordinary
     indeterminates (indeterminates having 0 for their `vtype').

   * Kernel sub-type of indeterminates created by `uc()' is 1.
     (`vtype(uc())'=1)

     [0] A=uc();
     _0
     [1] B=uc();
     _1
     [2] (uc()+uc())^2;
     _2^2+2*_3*_2+_3^2
     [3] (A+B)^2;
     _0^2+2*_1*_0+_1^2

References
     *Note `vtype': vtype, *Note `rtostr': rtostr, *Note `strtov':
     strtov.

