map(Module,Nothing,List)

map(M,,v) -- construct a map from a free graded module to M whose entries are obtained from the doubly-nested list v of ring elements.

The absence of the second argument indicates that the source of the map is to be a free module constructed with an attempt made to assign degrees to its basis elements so as to make the map homogeneous of degree zero.

     i1 = R = ZZ/101[x,y]
     
     o1 = R
     
     o1 : PolynomialRing

     i2 = f = map(R^2,,{{x^2,y^2},{x*y,0}})
     
     o2 = | x2 y2 |
          | xy 0  |
     
                  2       2
     o2 : Matrix R  <--- R

     i3 = degrees source f
     
     o3 = {{2},{2}}
     
     o3 : List

     i4 = isHomogeneous f
     
     o4 = true