`dp_homo', `dp_dehomo'
----------------------

dp_homo(DPOLY)
     :: Homogenize a distributed polynomial

dp_dehomo(DPOLY)
     :: Dehomogenize a homogenious distributed polynomial

RETURN
     distributed polynomial

DPOLY
     distributed polynomial

   * `dp_homo()' makes a copy of DPOLY, extends the length of the
     exponent vector of each term T in the copy by 1, and sets the
     value of the newly appended component to D-`deg(T)', where D is
     the total degree of DPOLY.

   * `dp_dehomo()' make a copy of DPOLY and removes the last component
     of each terms in the copy.

   * Appropriate term orderings must be set when the results are used
     as inputs of some operations.

   * These are used internally in `hgr()' etc.

     [202] X=<<1,2,3>>+3*<<1,2,1>>;
     (1)*<<1,2,3>>+(3)*<<1,2,1>>
     [203] dp_homo(X);
     (1)*<<1,2,3,0>>+(3)*<<1,2,1,2>>
     [204] dp_dehomo(@);
     (1)*<<1,2,3>>+(3)*<<1,2,1>>

References
     *Note `gr hgr gr_mod': gr hgr gr_mod.

