This computes the homology of a differential module. More specifically: since we interpret differential modules as 3-term complexes, this returns the zeroth homology module.
i1 : R = QQ[x,y]
o1 = R
o1 : PolynomialRing
i2 : M = R^1/ideal(x^2,y^2)
o2 = cokernel | x2 y2 |
1
o2 : R-module, quotient of R
i3 : phi = map(M,M,x*y)
o3 = | xy |
o3 : Matrix M <-- M
i4 : D = differentialModule phi
o4 = M <-- M <-- M
-1 0 1
o4 : DifferentialModule
i5 : HH D
o5 = subquotient (| y -x |, | xy x2 y2 |)
1
o5 : R-module, subquotient of R