On 01/04/2007 12:13 PM, Martin Rubey wrote: > Dear all, > > I'm sick, so just a short update and reply.
Please don't answer my mails. Go to bed and recover. Get well soon. >> But still, the problem is finite and thus solvable in principle by applying >> all permutations from S_n and building cosets. > > I don't think this is entirely true. What we need for a "stupid" algorithm to > do the unlabelled case - not the cases "inbetween" - is a function in, say, > CartesianProduct > > coerce: % -> IsomorphismType > > that yields the isomorphism Type of a structure. Please show me how to do that > for the Cartesian Product! (This would be the equivalent to having a normal > form) If I define IsomorphismType to be Set(%) then the only thing I have to do in the coerce function to generate all orbit elements with respect to S_n. The orbit is a normal form if you like. An ugly one, I agree, but otherwise I see nothing wrong with it. > An alternative possibility is to generate the structures, and for each > generated structure check whether it is isomorphic to one of the structures > already generated. That's probably the same thing. Ralf ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Aldor-combinat-devel mailing list Aldor-combinat-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/aldor-combinat-devel
