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minimalPresentation(Module) -- minimal presentation of a module

Synopsis

Description

If the Module M is graded then the module N is a minimal presentation of M. If not, then an attempt is made to improve the presentation of M. An example follows.
R = ZZ/32003[a..d];
M = coker matrix {{a,1,b},{c,3,b+d}}
N = minimalPresentation M
peek N.cache
g = N.cache.pruningMap
g^-1
This function also works when M is a graded module, a chain complex, or a coherent sheaf.
I = ideal(a^2,b^3,c^4,d^7)
X = Proj R
J = (module I)~
minimalPresentation J

See also