[GAP Forum] Bug in HallSubgroup?

Benjamin Sambale benjamin.sambale at gmail.com
Thu May 22 08:10:02 BST 2014


Dear GAP people,

I'm using GAP 4.7.4 on arch linux 64 bit. Let

G:=AtlasGroup("M22.2");
S:=SylowSubgroup(G,7);
N:=Normalizer(G,S);
Size(N); # =42

Then the command HallSubgroup(N,[2,3]); works *sometimes*, but other 
times I get "Error, depths are not compatible with parent pcgs". 
Apparently, this is related to the initialization of G. Try:

for i in [1..10] do
     Print(i,"\n");
     G:=AtlasGroup("M22.2");
     S:=SylowSubgroup(G,7);
     N:=Normalizer(G,S);
     HallSubgroup(N,[2,3]);
od;

Best wishes,
Benjamin



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