Hi, On Tuesday, August 11, 2015 at 7:29:56 PM UTC+2, Volker Braun wrote: > > Your simplex is not a full-dimensional simplex, so its a bit of a question > of definition. >
I see. For me the question whether a polytope is simplicial is independent of the embedding, but any choice is fine as long as the documentation is reflecting all the caveats. > We could > > a) keep the "False" output but fix the docstring of is_simplicial to > require full dimensionality, or > > b) extend simplicial-ness to general polyhedra. Then they obviously aren't > the duals of simple polytopes any more. > > Preferences? > I lean towards b, but I have no strong preference. With a), just make it clear in the documentation. With b) probably also some doc changes are necessary, but it seems a little more consistent. If the polar contains lines, then it's not a "simple polytope", for sure. Cheers, Thomas > > > > On Tuesday, August 11, 2015 at 4:38:26 PM UTC+2, Thomas Kahle wrote: >> >> Hi, >> >> I've stumbled upon the following polyhedron on which sage gives >> contradictory answers. This is sage-6.8. Is this a bug? >> >> sage: Pw >> A 7-dimensional polyhedron in QQ^16 defined as the convex hull of 8 >> vertices >> >> sage: Pw.vertices() >> (A vertex at (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0), >> A vertex at (1/3, 0, 0, 1/3, 0, 0, 0, 0, 0, 0, 0, 0, 1/3, 0, 0, 1/3), >> A vertex at (1/3, 0, 1/3, 0, 0, 0, 0, 0, 1/3, 0, 1/3, 0, 0, 0, 0, 0), >> A vertex at (1/9, 0, 1/9, 1/9, 0, 0, 0, 0, 1/9, 0, 1/9, 1/9, 1/9, 0, >> 1/9, 1/9), >> A vertex at (1/3, 1/3, 0, 0, 1/3, 1/3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0), >> A vertex at (1/9, 1/9, 0, 1/9, 1/9, 1/9, 0, 1/9, 0, 0, 0, 0, 1/9, 1/9, >> 0, 1/9), >> A vertex at (1/9, 1/9, 1/9, 0, 1/9, 1/9, 1/9, 0, 1/9, 1/9, 1/9, 0, 0, 0, >> 0, 0), >> A vertex at (1/27, 1/27, 1/27, 1/27, 1/27, 1/27, 1/27, 1/27, 1/27, 1/27, >> 1/27, 1/27, 1/27, 1/27, 1/27, 1/27)) >> >> sage: Pw.is_simplex() >> True >> sage: Pw.is_simplicial() >> False >> >> Of course the last should come out "True" >> >> Cheers, >> Thomas >> > -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
