> I would have guessed that P.to_graph() returns a digraph. Then you expected either P.hasse_diagram() or P.hasse_diagram().transitive_closure().
> Could there be just Graph(Poset) and maybe even DiGraph(Poset)? Same problem, we would not know "which graph" or "which digraph" it represents. With P.hasse_diagram() or P.comparability_graph() we know. [1] > What is actually a Hasse diagram? A graph with vertices labeled as > integers from 0 to n-1, some positioning information used for plot(), what > else? Sage contains a HasseDiagram class that is not meant for users (many unchecked assumptions, like the 0..n-1 labelling). When you execute P.hasse_diagram() you get a digraph whose vertices are list(P). More information there: http://en.wikipedia.org/wiki/Hasse_diagram Also, if you have an acyclic digraph D, then Poset(D).hasse_diagram() == D.transitive_reduction() Nathann [1] We could even have an exception raised in case of Graph(P) that mention those methods. -- 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. For more options, visit https://groups.google.com/d/optout.
