isZero(FreeOIModuleMap) -- check if a free OI-module map is zero

i1 : P = makePolynomialOIAlgebra(2, x, QQ);

i2 : F = makeFreeOIModule(e, {2}, P);

i3 : installGeneratorsInWidth(F, 2);

i4 : b = e_(2,{1,2},1);

i5 : C = oiRes({b}, 2)

o5 = 0: (e0, {2}, {0})
     1: (e1, {}, {})
     2: (e2, {}, {})

o5 : OIResolution

i6 : phi0 = C.dd_0

o6 = Source: (e0, {2}, {0}) Target: (e, {2}, {0})

o6 : FreeOIModuleMap

i7 : phi1 = C.dd_1

o7 = Source: (e1, {}, {}) Target: (e0, {2}, {0})

o7 : FreeOIModuleMap

i8 : isZero phi0

o8 = false

i9 : isZero phi1

o9 = true