[GAP Forum] RationalClass?

[Alexander Konovalov]

Dear Keith,

There is no function IsRationalConjugate in GAP 4.4.5.

The simplest implementation is the following one:

        IsRationalConjugate := function(G,g,h)
        return h in RationalClass(G,g);
        end;

A more proper approach is to install IsRationalConjugate as an operation:

DeclareOperation( "IsRationalConjugate", 
                 [ IsGroup, 
                   IsMultiplicativeElementWithInverse, 
                   IsMultiplicativeElementWithInverse ] );

InstallMethod( IsRationalConjugate,
              "for group elements",
               IsCollsElmsElms,
             [ IsGroup, 
               IsMultiplicativeElementWithInverse,
               IsMultiplicativeElementWithInverse ],
function(g,x,y)
  return y in RationalClass(g,x);
end);

Hope this helps.

Best wishes,
Alexander Konovalov



On Tuesday, August 16, 2005 at 5:19:14 PM 
R. Keith Dennis <dennis at rkd.math.cornell.edu> wrote:

> This is probably a silly question which is answered in the manual
> somewhere, but I didn't find it:

> Is there a function analogous to "IsConjugate" which does the same
> sort of thing for rational conjugacy classes, maybe something like
> IsRationalConjugate?

> If not, what's the most computationally efficient way of implementing
> it?

> Thanks!

> Keith