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change field for polynomials and ideals
ZPQ(F: RINGELEM): RINGELEM
ZPQ(F: LIST of RINGELEM): LIST of RINGELEM
ZPQ(I: IDEAL): IDEAL 
***** NOT YET IMPLEMENTED *****
The function
ZPQ
maps a polynomial with finite field coefficients
into one with rational (actually, integer) coefficients. It is not
uniquely defined mathematically, and currently for each coefficient
the least nonnegative equivalent integer is chosen.
Users should not rely on this choice, though any change will be
documented.
See
QZP
for more details.
use R ::= QQ[x,y,z];
F := 1/2*x^3 + 34/567*x*y*z  890;  a poly with rational coefficients
use S ::= ZZ/(101)[x,y,z];
QZP(F);  compute its image with coeffs in ZZ/(101)
50x^3  19xyz + 19

G := It;
use R;
ZPQ(G);  now map that result back to QQ[x,y,z] it is NOT the same as F...
51x^3 + 82xyz + 19

