I am trying to work with graphs in MAGMA, but to my surprise I noticed that the vertices of the graph are no longer considered elements of the set I started with. Here is an example:
X:={1.. 13}; g:=Graph< X | { {u,v} : u,v in X |(u-v)^6 mod 13 eq 1}>; Random(Vertices(g)) in X;
The output is:
Runtime error in 'in': No valid universe containing all elements
This is a bit unfortunate for my purposes, because I want to construct cliques and cocliques and then compare this to other structural relations in the original set. How can I solve this?
Many thanks, Kind regards