73.97 SectionDerivation

SectionDerivation( D, i )

This function converts a derivation of X to a section of the associated cat1-group C. This function is inverse to DerivationSection. In the following examples we note that allXSC has been obtained using allSC, so the derivations and sections correspond in the same order.

    gap> chi8 := XModDerivationByImages( XSC, allXSC.genimageList[8] );
    XModDerivationByImages( s3, c3, [ (4,5,6), (2,3)(5,6) ], 
       [ ( 1,2,3)(4,6,5), (1,2,3)(4,6,5) ] )
    gap> xi8 := SectionDerivation( chi8 );
    GroupHomomorphismByImages( s3, c3^2

Xc2,
        [ (4,5,6), (2,3)(5,6) ], [ (1,2,3), (1,2)(4,6) ] )  

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