prune(DGModule) -- Pruning a DG module is the identity

Function: prune
Usage:

Mp = prune M

Mp = minimalPresentation M
Inputs:
- M, an instance of the type DGModule,
Optional inputs:
- Exclude => ..., default value {},
Outputs:
- Mp, an instance of the type DGModule, The same DG module M. A pruningMap equal to the identity DG module map on M is cached in M.cache.

Description

DG modules as stored in this package (built from freeDGModule or koszulComplexDGM) carry no auxiliary presentation data that prune could minimize; the method is installed as the identity so that calling code can use prune uniformly across DG types.

Calling prune M has the side effect of caching an identity DGModuleMap under the symbol pruningMap in M.cache.

minimalPresentation is a synonym for prune.

i1 : R = ZZ/101[x]

o1 = R

o1 : PolynomialRing

i2 : A = koszulComplexDGA R

o2 = {Ring => R                    }
      Underlying algebra => R[T   ]
                               1,1
      Differential => {x}

o2 : DGAlgebra

i3 : M = freeDGModule(A, {0, 1})

o3 = {Base ring => R                       }
      DG algebra => R[T   ]
                       1,1
                                 2
      Natural module => (R[T   ])
                            1,1
      Generator degrees => {{0, 0}, {1, 0}}
      Differentials on gens => {0, 0}

o3 : DGModule

i4 : (prune M) === M

o4 = true

i5 : (minimalPresentation M) === M

o5 = true

Ways to use this method:

prune(DGModule) -- Pruning a DG module is the identity

The source of this document is in /build/reproducible-path/macaulay2-1.26.05+ds/M2/Macaulay2/packages/DGAlgebras/doc.m2:4723:0.

prune(DGModule) -- Pruning a DG module is the identity

Description

See also

Ways to use this method: