isSubset(Module,Module) -- whether one object is a subset of another

i1 : R = QQ[x,y]

o1 = R

o1 : PolynomialRing

i2 : M = image matrix {{x,0},{0,y}}

o2 = image | x 0 |
           | 0 y |

                             2
o2 : R-module, submodule of R

i3 : N = image matrix {{x^2,0},{-y,y}}

o3 = image | x2 0 |
           | -y y |

                             2
o3 : R-module, submodule of R

i4 : isSubset(N,M)

o4 = true

i5 : isSubset(M,N)

o5 = false