ChainComplex _ ZZ -- get component

ChainComplex _ ZZ -- get component

C_i -- yields the i-th module in a chain complex C.

Returns the zero module if no module has been stored in the i-th spot. You can use code like C#?i to determine if there is a module in the i-th spot, but if the chain complex arose as a resolution, first use complete ChainComplex to fill all the spots with their modules.

Synopsis of use:

Operator: _

Class of argument 1: ChainComplex

Class of argument 2: ZZ

Class of typical returned value: Module

Next more general method: GradedModule _ ZZ