Dear all, I'm sick, so just a short update and reply.
Update: I modified most of species.as.nw to deal with "generalized" isomorphismtypes as announced and maybe better explained by Ralf (I don't have the energy to read his mail really, though. I have algorithms for Compose, Derive, Point for labelled, unlabelled and everything inbetween. I don't have a clue how to do Cartesian products and Functorial Composition, except for the labelled case or in special cases. (for example, pointing is a special case of the cartesian product) > 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) 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. But really, I think the best would be to find a way to cast the problem into the problem of generating all nonisomorphic graphs or designs and use nauty to generate them. However, it is very unlikely that this is possible at all. I guess, generating the isomorphismtypes of an arbitrary cartesian product is a real challenge. Martin ------------------------------------------------------------------------- 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
