[GAP Forum] GRAPE: using trivial group

[Leonard Soicher]

Dear Frédéric, Dear GAP-Forum,

> but this doesn't work;
> 
> LoadPackage("grape");
> q:=13;
> gf:=GaloisField(q);
> graph:=Graph(Group(()), Elements(gf), OnPoints,function(x,y) return
> (x-y)^((q-1)/2)=One(gf); end,true);
> 
> It's probably just a matter of defining the trivial group on the
> right set in the proper way, but how should one do this?

What I suggest is to define a function for the trivial action of a group: 

trivialaction := function(x,g) return x; end;

Then the following will work:

LoadPackage("grape");
q:=13;
gf:=GaloisField(q);
graph:=Graph(Group(()), Elements(gf), trivialaction, function(x,y) return 
(x-y)^((q-1)/2)=One(gf); end,true);

All the best,
Leonard