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unfold -- converts a differential module into a 1-periodic complex

Synopsis

Description

Given a differential module D and integers a and b, this method produces a chain complex with the module D in homological degrees a through b, where all maps are the differential of D.

i1 : phi = matrix{{0,1},{0,0}};

              2       2
o1 : Matrix ZZ  <-- ZZ
i2 : D = differentialModule(phi);
i3 : unfold(D,-3,4)

       2       2       2       2       2       2       2       2       2
o3 = ZZ  <-- ZZ  <-- ZZ  <-- ZZ  <-- ZZ  <-- ZZ  <-- ZZ  <-- ZZ  <-- ZZ
                                                                      
     -3      -2      -1      0       1       2       3       4       5

o3 : ChainComplex

See also

Ways to use unfold :

For the programmer

The object unfold is a method function.