I had asked GAP Forum the follwoing question
Here is my question:
I have a set S with 30 elements, together with a symmetric binary relation R, which
holds between some of the elements of S. I would like to find out all the
permutations of S which preserve the relation R, in the following precise sense
f: S to S, f bijection satisfying "a R b if and only if f(a) R f(b)".
Is there any program in GAP that would allow me to do that?
and have received the answer that grape would do it. I went to a computer with gap
installed on it, read the book containing the documentation on it, and have tried first
with a small example to see whether the whole thing works, and to my surprise have
found that it doesn't. Here is what I did. I defined
gamma := EdgeOrbitsGraph( Group( () ), [[1,2],[2,3],[2,1],[3,2]], 5 )
followed by eithe ; or ;; regardless of which produced the message from gap that
EdgeOrbitsGraph requires a value for the variable. I have tried to leave no spaces,
and small cahnges of the kind, all to no avail.