Miscellaneous

SL2Z
SL2Z(p)
SL2Z(1/m)

Inputs a prime p or the reciprocal 1/m of a square free integer m. In the first case the function returns the conjugate SL(2,Z)^P of the special linear group SL(2,Z) by the matrix P=[[1,0],[0,p]]. In the second case it returns the group SL(2,Z[1/m]).

BigStepLCS
BigStepLCS(G,n)

Inputs a group G and a positive integer n. It returns a subseries G=L_1&tgt;L_2&tgt; \ldots L_k=1 of the lower central series of G such that L_i/L_{i+1} has order greater than n.
Classify
Classify(L,Inv)

Inputs a list of objects L and a function Inv which computes an invariant of each object. It returns a list of lists which classifies the objects of L according to the invariant..
RefineClassification
RefineClassification(C,Inv)

Inputs a list C:=Classify(L,OldInv) and returns a refined classification according to the invariant Inv.
Compose(f,g)
Compose(f,g)

Inputs two FpG-module homomorphisms f:M \longrightarrow N and g:L \longrightarrow M with Source(f)=Target(g) . It returns the composite homomorphism fg:L \longrightarrow N .

This also applies to group homomorphisms f,g.
HAPcopyright
HAPcopyright()

This function provides details of HAP'S GNU public copyright licence.
IsLieAlgebraHomomorphism
IsLieAlgebraHomomorphism(f)

Inputs an object f and returns true if f is a homomorphism f:A \longrightarrow B of Lie algebras (preserving the Lie bracket).
IsSuperperfect
IsSuperperfect(G)

Inputs a group G and returns "true" if both the first and second integral homology of G is trivial. Otherwise, it returns "false".
MakeHAPManual
MakeHAPManual()

This function creates the manual for HAP from an XML file.
PermToMatrixGroup
PermToMatrixGroup(G,n)

Inputs a permutation group G and its degree n. Returns a bijective homomorphism f:G \longrightarrow M where M is a group of permutation matrices.
SolutionsMatDestructive
SolutionsMatDestructive(M,B)

Inputs an m×n matrix M and a k×n matrix B over a field. It returns a k×m matrix S satisfying SM=B.

The function will leave matrix M unchanged but will probably change matrix B.

(This is a trivial rewrite of the standard GAP function SolutionMatDestructive(&tlt;mat&tgt;,&tlt;vec&tgt;) .)
LinearHomomorphismsPersistenceMat
LinearHomomorphismsPersistenceMat(L)

Inputs a composable sequence L of vector space homomorphisms. It returns an integer matrix containing the dimensions of the images of the various composites. The sequence L is determined up to isomorphism by this matrix.
NormalSeriesToQuotientHomomorphisms
NormalSeriesToQuotientHomomorphisms(L)

Inputs an (increasing or decreasing) chain L of normal subgroups in some group G. This G is the largest group in the chain. It returns the sequence of composable group homomorphisms G/L[i] \rightarrow G/L[i+/-1].
TestHap
TestHap()

This runs a representative sample of HAP functions and checks to see that they produce the correct output.