Dear GAP Forum,
X-Miles: GAP Forum article 127 accepted at 31 Jan 98 10:29 +0100 Date: Sat, 31 Jan 98 10:29:06 +0000 From: Kaustuv M. Das <cfkmd@ux1.cts.eiu.edu> To: Multiple recipients of list <GAP-Forum@dcs.st-and.ac.uk> Subject: Action of G on CayleyGraph(G)
If I do the following (assuming Distance(Gamma,1,44) = Diameter(Gamma) ):
Distance(Gamma, VertexName(Gamma,44)*s1, 1);
where s1 is an involution in the generating set I get the obvious error
message that VertexName(Gamma, 44)*s1 is not a vertex of Gamma. (It is a
vertex name, but that doesn't seem to help.)
Yes, vertex names are in this case disjoint from vertices.
A general solution (would work for whatever (GRAPE) graphs
would be to define
VertexIndex := function(graph, vertexname)
return Position(graph.names, vertexname);
end;
and use (in your case)
Distance(Gamma, VertexIndex(Gamma, VertexName(Gamma,44)*s1), 1);
Hope this helps,
Dmitrii
d.pasechnik@twi.tudelft.nl
http://ssor.twi.tudelft.nl/~dima