image [OBSOLESCENT] -- [OBSOLESCENT] apply ring homomorphism |
Description |
Example |
/**/ use Dom ::= QQ[x,y]; -- domain /**/ f := x-y; -- a RINGELEM in D /**/ use Cod ::= QQ[a,b,c]; -- codomain /**/ -- the old trick /**/ -- Phi := RMap(a, c^2-a*b); -- OBSOLESCENT /**/ -- Image(f, Phi); -- OBSOLESCENT a*b -c^2 +a /**/ -- the proper call /**/ phi := PolyAlgebraHom(Dom, Cod, [a, c^2-a*b]); -- a RINGHOM /**/ phi(f); a*b -c^2 +a /**/ phi([f, f^2]); [a*b -c^2 +a, a^2*b^2 -2*a*b*c^2 +c^4 +2*a^2*b -2*a*c^2 +a^2] |
See Also |