ChainComplex ++ ChainComplex -- direct sum

ChainComplex ++ ChainComplex -- direct sum

Synopsis:

Operator: ++ -- a binary operator, usually used for direct sum

Input:

an instance of class ChainComplex.

Output:

an instance of class ChainComplex.

Next more general method: GradedModule ++ GradedModule -- a binary operator, usually used for direct sum

C++D -- direct sum of chain complexes.

i1 : C = resolution cokernel matrix {{4,5}}



       1       2       1

o1 = ZZ  <-- ZZ  <-- ZZ

                      

     0       1       2



o1 : ChainComplex

i2 : C ++ C[-2]



       1       2       2       2       1

o2 = ZZ  <-- ZZ  <-- ZZ  <-- ZZ  <-- ZZ

                                      

     0       1       2       3       4



o2 : ChainComplex

Code:

     -- ../../../Macaulay2/m2/chaincomplexes.m2:526
     ChainComplex ++ ChainComplex := ChainComplex => (C,D) -> directSum(C,D)