Cat1MorphismOps.CompositeMorphism( mu1,mu2 )
Morphisms mu_1 : C to D and mu_2 : D to E have a composite mu = mu_2 circ mu_1 : C to E whose source and range homomorphisms are the composites of those of mu_1 and mu_2. The example corresponds to that in refCompositeMorphism for crossed modules.
gap> psi; Morphism of crossed modules <[c4->q8] >-> [c4->q8]> gap> inc; Morphism of crossed modules <[c4->q8] >-> [q8->sl(2,3)]> gap> mupsi := Cat1MorphismXModMorphism( psi ); Morphism of cat1-groups <[Perm(q8
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X c4) ==> q8]-->[Perm(q8
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X c4) ==> q8]> gap> muinc := Cat1MorphismXModMorphism( inc ); Morphism of cat1-groups <[Perm(q8
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X c4) ==> q8]-->[Perm(sl(2,3)
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X q8) ==> sl(2,3)]> gap> mucomp := Cat1MorphismOps.CompositeMorphism( mupsi, muinc ); Morphism of cat1-groups <[Perm(q8
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X c4) ==> q8]-->[Perm(sl(2,3)
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X q8) ==> sl(2,3)]> gap> muxcomp := Cat1MorphismXModMorphism( xcomp );; gap> mucomp = muxcomp; true
GAP 3.4.4