[GAP Forum] irreducible representations of the dihedral group D10 over GF(4)

[Alexander Konovalov]

On 12 Jul 2012, at 17:58, Neha Makhijani <nehamakhijani at gmail.com> wrote:

> Can somebody please clarify as to why I am not able to get the irreducible
> representations of the dihedral group over GF(4)??
> 
> IrreducibleRepresentations(DihedralGroup(10),GF(2^2));
> List Element: <position> must be a positive integer (not a boolean)
> 
> Thanks!
> 
> Neha

Dear Neha,

Sorry it took longer than we expected to fix this. Just released GAP 4.6.3 
provides the default method for AbsoluteIrreducibleModules as a temporary 
workaround for the problem which may cause returning wrong results or 
producing an error when being called for a non-prime field. As a result,
your example now works:

gap> IrreducibleRepresentations(DihedralGroup(10),GF(2^2));
[ [ f1, f2 ] -> [ [ [ Z(2)^0 ] ], [ [ Z(2)^0 ] ] ], 
  [ f1, f2 ] -> [ [ [ Z(2^2), Z(2)^0 ], [ Z(2^2), Z(2^2) ] ], 
      [ [ 0*Z(2), Z(2)^0 ], [ Z(2)^0, Z(2^2) ] ] ], 
  [ f1, f2 ] -> [ [ [ Z(2^2)^2, Z(2^2)^2 ], [ Z(2)^0, Z(2^2)^2 ] ], 
      [ [ Z(2^2)^2, Z(2)^0 ], [ Z(2)^0, 0*Z(2) ] ] ] ]

Best wishes,
Alexander