## Description

C**D -- the tensor product of two chain complexes.

The result,

E, is a chain complex. Each module

E_k in it is a direct sum of modules of the form

C_i**D_j with

i+j=k, and the preferred keys for the components of this direct sum are the pairs

(i,j), sorted increasing values of

i. For information about how to use preferred keys, see

directSum.