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#############################################################################
##
#W crystcat.grp GAP library Franz G"ahler
##
#Y Copyright (C) 1997, Lehrstuhl D fuer Mathematik, RWTH Aachen, Germany
##
InstallMethod( NormalizerInGLnZ,
"for PointGroups of space groups from the cryst. groups catalogue",
true, [ IsPointGroup and IsCyclotomicMatrixGroup ], 0,
function( P )
local S, p, N, s, gen;
S := AffineCrystGroupOfPointGroup( P );
if not HasCrystCatRecord( S ) then
TryNextMethod();
fi;
p := CrystCatRecord( S ).parameters;
N := NormalizerZClass( p[1], p[2], p[3], p[4] );
s := Size( N );
if IsAffineCrystGroupOnRight( S ) then
gen := List( GeneratorsOfGroup( N ), TransposedMat );
N := GroupByGenerators( gen, One( N ) );
SetSize( N, s );
fi;
return N;
end );
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