On Tue, Mar 25, 2025 at 06:04:30PM -0400, Jackson Walters wrote:
> Thanks, that's helpful.
>
> G = graphs.GrassmannGraph(5, 4, 2); G
>
> gives 806 vertices, as expected, but why do the vertices seem to have six
> points?
>
> G.vertices()[0]
> {(0, 0, 0, 1), (1, 0, 0, 1), (1, 0, 0, 2), (1, 0, 0, 4), (1, 0, 0, 0), (1,
> 0, 0, 3)}
>
> I don't see anything about this in the documentation. Shouldn't it be just
> two basis vectors that span the subspace?The 3rd parameter, the dimension of the subspaces, is equal to 2. Thus these are all the q+1 (projective) points in the projective line over GF(q), with q=5. It was a quick and not optimised coding. If you would like to change this to a more economic representation, please open a PR. As the documentation doesn't say anything about a particular way the subspaces are represented, it can be changed quickly, no deprecation would be needed. Dima > > Thanks, > Jackson > > On Tue, Mar 25, 2025 at 5:33 PM Dima Pasechnik <dimp...@gmail.com> wrote: > > > We have functionality to build Grassmann graphs. See GrassmannGraph in > > > > < > > https://doc.sagemath.org/html/en/reference/graphs/sage/graphs/graph_generators.html#sage.graphs.graph_generators.graphgenerators.paleygraph > > > > > > > > > On 25 March 2025 12:46:56 GMT-05:00, Jackson Walters < > > jacksonwalt...@gmail.com> wrote: > > > >> Does Sage support computing Gr_{F_q}(k,r), the space of k-hyperplanes > >> through the origin in GF(q**r)? I looked around for things like Schubert > >> cells and didn't see anything immediately relevant. I've started to write > >> some stuff for k=2. I may do a PR if it's not already available. > >> > >> Thanks, > >> Jackson > >> > >> -- > > 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 view this discussion visit > > https://groups.google.com/d/msgid/sage-devel/68A3261B-8643-43BC-BFBF-AB2DBF9D89FB%40gmail.com > > <https://groups.google.com/d/msgid/sage-devel/68A3261B-8643-43BC-BFBF-AB2DBF9D89FB%40gmail.com?utm_medium=email&utm_source=footer> > > . > > > > -- > 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 view this discussion visit > https://groups.google.com/d/msgid/sage-devel/CAGqtwVBaOiXUP4NJiW%2BF1nY9k5Zjmhp4tSuH%3DSNvtSS1xtwhWA%40mail.gmail.com. -- 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 view this discussion visit https://groups.google.com/d/msgid/sage-devel/Z-N54P4zuGgbah1s%40tarski.
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