IsSurjective -- check if a RINGHOM is surjective |
Syntax |
IsSurjective(phi: RINGHOM): BOOL |
Description |
Example |
/**/ QQxyz ::= QQ[x,y,z]; /**/ QQab ::= QQ[a,b]; /**/ use QQab; /**/ phi := PolyAlgebraHom(QQxyz, QQab, [a+1, a*b+3, b^2]); ideal(-x^2*z +y^2 +2*x*z -6*y -z +9) /**/ IsSurjective(phi); false /**/ preimage0(phi, b); 0 |
See Also |