If
X is a module then it must be either free or a submodule of a free module. If
X is a chain complex, then every module of
X must be free or a submodule of a free module.
i1 : R = QQ[x,y];
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i2 : S = QQ[t];
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i3 : f = map(S,R,{t^2,t^3})
2 3
o3 = map(S,R,{t , t })
o3 : RingMap S <--- R
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i4 : f (x+y^2)
6 2
o4 = t + t
o4 : S
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i5 : f image vars R
o5 = image | t2 t3 |
1
o5 : S-module, submodule of S
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i6 : f ideal (x^2,y^2)
4 6
o6 = ideal (t , t )
o6 : Ideal of S
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i7 : f resolution coker vars R
1 2 1
o7 = S <-- S <-- S <-- 0
0 1 2 3
o7 : ChainComplex
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