Dear Forum,

Could you tell me why I can not get Cohomology from the following.

(This is a log of GAP4r1.)

gap> g:=GL(2,2);;
gap> pgl:=Action(g,Orbit(g,One(GF(2))*[1,0],OnLines),OnLines);;
gap> iso_g:=IsomorphismPcGroup(pgl);;
gap> G:=Image(iso_g);;
gap> mats:=MutableCopyMat(GeneratorsOfGroup(g));;
gap> M:=GModuleByMats(mats,GF(2));;
gap> TwoCoboundaries( G, M );
[ [ 0*Z(2), Z(2)^0, 0*Z(2), 0*Z(2), 0*Z(2), 0*Z(2) ], 
  [ 0*Z(2), 0*Z(2), Z(2)^0, 0*Z(2), 0*Z(2), 0*Z(2) ], 
  [ 0*Z(2), 0*Z(2), 0*Z(2), 0*Z(2), Z(2)^0, 0*Z(2) ], 
  [ 0*Z(2), 0*Z(2), 0*Z(2), 0*Z(2), 0*Z(2), Z(2)^0 ] ]
gap> TwoCocycles( G, M );
[ [ 0*Z(2), Z(2)^0, 0*Z(2), 0*Z(2), 0*Z(2), 0*Z(2) ], 
  [ 0*Z(2), 0*Z(2), Z(2)^0, 0*Z(2), Z(2)^0, Z(2)^0 ] ]
gap> cc := TwoCohomology( G, M );;
AppendList: <list2> must be a list (not a object (positional)) at
Append( cat, lst );
Concatenation( List( Wvectors, function ( v )
        return zero;
    end ), BasisVectors( canbas ) ) called from
NaturalHomomorphismBySubspaceOntoFullRowSpace( co, cb ) called from
<function>( <arguments> ) called from read-eval-loop
Entering break read-eval-print loop, you can 'quit;' to quit to outer loop,
or you can return a list for <list2> to continue

Katsushi Waki + Hirosaki University +