HAP home
Top of Book Previous Chapter Next Chapter

20. Some functions for accessing basic data

### 20. Some functions for accessing basic data

`BoundaryMap(C)` Inputs a resolution, chain complex or cochain complex C and returns the function C!.boundary.
`BoundaryMatrix(C,n)` Inputs a chain or cochain complex C and integer n>0. It returns the n-th boundary map of C as a matrix.
`Dimension(C)` `Dimension(M)` Inputs a resolution, chain complex or cochain complex C and returns the function C!.dimension . Alternatively, inputs an FpG-module M and returns its dimension as a vector space over the field of p elements.
`EvaluateProperty(X,"name")` Inputs a component object X (such as a ZG-resolution or chain map) and a string "name" (such as "characteristic" or "type"). It searches X.property for the pair ["name",value] and returns value. If X.property does not exist, or if ["name",value] does not exist, it returns fail.
`GroupOfResolution(R)` Inputs a ZG-resolution R and returns the group G.
`Length(R)` Inputs a resolution R and returns its length (i.e. the number of terms of R that HAP has computed).
`Map(f)` Inputs a chain map, or cochain map or equivariant chain map f and returns the mapping function (as opposed to the target or the source of f) .
`Source(f)` Inputs a chain map, or cochain map, or equivariant chain map, or FpG-module homomorphism f and returns it source.
`Target(f)` Inputs a chain map, or cochain map, or equivariant chain map, or FpG-module homomorphism f and returns its target.

Top of Book Previous Chapter Next Chapter
Goto Chapter: Top 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Ind

generated by GAPDoc2HTML