On May 13, 9:14 pm, Jason Bandlow <[email protected]> wrote:
> In principle, CombinatorialFreeModule is exactly the right tool for > this. As Florent pointed out, this class has no difficulties with > infinite sets. The problem is that the objects that make up your basis > must be immutable. Almost all of the things that one might call > 'combinatorial objects' in sage are immutable, in large part so that > they can be used in this way. Unfortunately, that is not the case for > graphs. So I don't know how to solve your problem. Maybe someone else > knows how create a dummy class whose objects are immutable graphs? I used graphs as an example. I want to write my own class of planar graphs. Can I make them immutable? Another problem is that Nicolas said they also needed to be hashable - I haven't yet figured out whether that is feasible. Thirdly I want to consider planar graphs up to isomorphism (luckily I don't have to worry about automorphisms of objects in this case). I have say "edges" with maps and which I have to name to define the maps etc. However if I change the labels I regard this as the same "graph" whereas I suspect sage would by default regard them as different. I can think of hash functions which are the same for isomorphic planar graphs but I haven't come up with anything reasonable such that the hash values are the same if and only if the planar graphs are isomorphic. -- You received this message because you are subscribed to the Google Groups "sage-combinat-devel" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sage-combinat-devel?hl=en.
