On Friday, February 1, 2013 11:41:40 AM UTC, jori.ma...@uta.fi wrote: > If I understand correctly, after conjugacy_class(self, g) is done it needs > only say conjugacy_class(self, g1)==conjugacy_class(self, g2) to check if > two groups are conjugates. (But still, for convenience there should be > is_conjugate() -funktion.) >
That is of course a possibility, but is not very efficient for large groups. A slightly better choice would be testing g2 in G.conjugacy_class(g1) but even that requires computing the full conjugacy class before giving an answer. If the group G is large this is not very efficient, so having an is_conjugate method is useful whenever there are ways of speeding up the computation (or limiting the memory use) so I would rather restrict to use g2 in G.conjugacy_class(g1) as a fallback method in case nothing else works, i.e. try to use GAP fast method first, if that fails check the order of the elements (or the cycle decomposition shape if in a permutation group) and any other quick invariant one can think of, and only if all these agree then fall back to computing the full conjugacy class. Whatever implementation you go with, yes, having an is_conjugate method for group elements would be great. J -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
