Hi all: This issue is undocumented and seems odd to me. I could not find it mentioned in sage-support before.
sage: Gamma1 = graphs.CompleteGraph(4); Gamma1 Complete graph: Graph on 4 vertices sage: V1 = Gamma1.vertices(); V1 [0, 1, 2, 3] sage: E1 = Gamma1.edges(); E1 [(0, 1, None), (0, 2, None), (0, 3, None), (1, 2, None), (1, 3, None), (2, 3, None)] sage: Gamma1.incidence_matrix() [-1 -1 -1 0 0 0] [ 0 0 1 -1 -1 0] [ 0 1 0 0 1 -1] [ 1 0 0 1 0 1] In other words, if you look at the ordering of the edges of Gamma1 determined by the incidence matrix that Sage returns, the first edge (indicated by the first column) is (0,3). However, if you look at the ordering of the edges of Gamma1 determined by the edges method, the first edge is (0,1). Maybe not a bug but an unusual feature? - David Joyner -- 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 http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
