map(Ring,Ring) -- make a map

map(Ring,Ring) -- make a map

Synopsis:

Function: map -- make a map

Input:

an instance of class Ring.

Output:

an instance of class RingMap.

Optional arguments :

map(..., Degree)

map(..., DegreeMap => ...)

Code:

     -- ../../../Macaulay2/m2/ringmap.m2:69-76
     map(Ring,Ring) := RingMap => options -> (S,R) -> (
          A := R; v := {}; while (
               v = join(apply(generators A, 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})))