ker |
Syntax |
ker(phi: RINGHOM): IDEAL |
Description |
Example |
/**/ R ::= QQ[x,y,z,w]; /**/ Use S ::= QQ[s,t]; /**/ phi := PolyAlgebraHom(R, S, [s^3, s^2*t, s*t^2, t^3]); /**/ ker(phi); ideal(z^2 -y*t, y*z -x*t, y^2 -x*z) /**/ SmodJ := NewQuotientRing(S, ideal(ReadExpr(S,"t+s"))); /**/ Use SmodJ; /**/ psi := PolyAlgebraHom(R, SmodJ, [s^3, s^2*t, s*t^2, t^3]); /**/ ker(psi); ideal(x +w, y -w, z +w) /**/ RmodI := NewQuotientRing(R, ideal(ReadExpr(R,"x+y"))); /**/ ker(InducedHom(RmodI, psi)); ideal((-y +w), (y -w), (z +w)) |
See Also |