On Thu, Mar 29, 2018 at 11:09 AM, Henri Girard <henri.gir...@gmail.com> wrote: > Very near... Thanks, I would like the circle inside it > > https://en.wikipedia.org/wiki/Fano_plane > > Do you know why sage choose matroid to make this graphics ?
The Fano plane is really a combinatorial object. See for example http://buzzard.pugetsound.edu/cs/section-15.html on how to use Sage to explore it. It just happens to have a nice picture associated to it, which the developers of the matroid module implemented. > > I just begin and my question might be nonsense. > > > > > Le 29/03/2018 à 16:48, David Joyner a écrit : >> >> On Thu, Mar 29, 2018 at 9:32 AM, Henri Girard <henri.gir...@gmail.com> >> wrote: >>> >>> Hi, >>> >>> I don' manage matroid well, is there no way for doing a fano's graph with >>> a >>> matrix ? >>> >>> After I could find adjacent and incident matrix apparently in matroid is >>> not >>> possible ? >> >> The fano matroid is not graphical >> https://en.wikipedia.org/wiki/Graphic_matroid#Minors_and_duality >> so it doesn't have an adjacency matrix in the sense of a graph. >> Here is a graph whose picture looks a bit like the standard image >> of the Fano matriod: >> >> sage: Gamma = >> Graph([(0,1),(0,2),(1,2),(1,3),(3,4),(1,4),(2,4),(2,5),(4,5)]) >> sage: A = Gamma.adjacency_matrix() >> sage: A >> [0 1 1 0 0 0] >> [1 0 1 1 1 0] >> [1 1 0 0 1 1] >> [0 1 0 0 1 0] >> [0 1 1 1 0 1] >> [0 0 1 0 1 0] >> >> I'm not sure if that is what you are looking for. >> >>> Any help welcome >>> >>> Henri >>> >>> -- >>> 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 sage-support+unsubscr...@googlegroups.com. >>> To post to this group, send email to sage-support@googlegroups.com. >>> Visit this group at https://groups.google.com/group/sage-support. >>> For more options, visit https://groups.google.com/d/optout. > > > -- > 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 sage-support+unsubscr...@googlegroups.com. > To post to this group, send email to sage-support@googlegroups.com. > Visit this group at https://groups.google.com/group/sage-support. > For more options, visit https://groups.google.com/d/optout. -- 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 sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at https://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
