On Thursday, March 29, 2018 at 2:46:22 PM UTC+1, HG wrote: > > > https://www.usna.edu/Users/math/wdj/_files/documents/teach/sm444/sm444_alg-graph-thry-notes.pdf > > This example (figure 4, page11) is the fano plane, I thaught the the > following example was how to make it but no.... > sage: for x in GF(7): > ....: L = [x+1,x+2,x+4] > ....: L.sort() > ....: print x, L > > B = matrix(ZZ,[[0,0,0,1,0,1,1],[1,0,0,0,1,0,1], > [1,1,0,0,0,1,0],[0,1,1,0,0,0,1], > [1,0,1,1,0,0,0],[0,1,0,1,1,0,0],[0,0,1,0,1,1,0]]) > > A = block_matrix(2, 2, [ B*0, B, B.transpose(), B*0 ]) > sage: Gamma = Graph(A, format=’adjacency_matrix’) > sage: Gamma.is_bipartite() >
this constructs the incidence point-line graph of the Fano plane. There is no regular way to draw configurations like the one you would like, other than indeed using points, lines, and circles... -- 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.
