Synopsis:
Code:
-- ../m2/ringmap.m2:64-72 map(Ring,Ring) := RingMap => options -> (S,R) -> ( A := R; v := {}; while ( if A.?generators then ( v = join(apply(A.generators, x -> ( x = toString x; if S#?x then S#x else 0_S )), v)); A.?ring) do A = A.ring; map(S,R,matrix (S,{v})))