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resolution(NCMatrix) -- Compute the resolution of coker M as a map of free right modules

Synopsis

Description

This function computes a minimal graded free resolution of the cokernel of M, considered as a map of graded right free modules. M must be homogeneous for this command to work.

As of this version, NCChainComplex (the return type) is still quite simple, though betti still works on them.

i1 : A = skewPolynomialRing(QQ,(-1)_QQ,{x,y,z})
--Calling Bergman for NCGB calculation.
Complete!

o1 = A

o1 : NCQuotientRing
i2 : M = ncMatrix {{x,y,z}}

o2 = | x y z |

o2 : NCMatrix
i3 : Mres = res M
--Calling Bergman for NCGB calculation.
Complete!
--Calling Bergman for NCGB calculation.
Complete!
--Calling Bergman for NCGB calculation.
Complete!

      1      3      3      1
o3 = A  <-- A  <-- A  <-- A
                           
     0      1      2      3

o3 : NCChainComplex
i4 : Mres#0

o4 = | x y z |

o4 : NCMatrix
i5 : Mres#1

o5 = | 0  -z -y |
     | -z 0  -x |
     | -y -x 0  |

o5 : NCMatrix
i6 : Mres#2

o6 = | -x |
     | -y |
     | -z |

o6 : NCMatrix
i7 : betti Mres

            0 1 2 3
o7 = total: 1 3 3 1
         0: 1 3 3 1

o7 : BettiTally

See also

Ways to use this method: