73.94 RegularSections

RegularSections( C [,"endo" rm or "xmod"] )

By default, this function computes the set of idempotent automorphisms from R to R and takes these as possible choices for hxi. A backtrack procedure then calculates possible images for such a section. The result is stored in a sections record C.sections with fields similar to those of a serivations record. The alternative strategy, for which "xmod" option should be specified is to calculate the regular derivations of the associated crossed module first, and convert the resulting derivations to sections.

    gap> Unbind( XSC.derivations );
    gap> regSC := RegularSections( SC );
    RegularSections record for cat1-group [c3^2
|
Xc2 ==> s3],
    : 6 regular sections, others not found.  

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GAP 3.4.4
April 1997