That matrix comes from the paper by J.Hempel: "Homology of covering" Pac. J. Math. vol 112 (1984) 83, example 5.2. The author says that it presents Z5
Il giorno mercoledì 24 marzo 2021 alle 08:50:18 UTC+1 vdelecroix ha scritto: > Your matrix has determinant 4 - 9 = -5. Hence, the group it generates > in GL(2,QQ) is necessarily infinite. > > Le 24/03/2021 à 08:47, Mattia Villani a écrit : > > I do not have real code, only a matrix: > > > > matrix([[1,-3],[-3,4]]) > > > > which should be a representation of the group Z5: I want to verify it > with > > Sage > > > > Il giorno martedì 23 marzo 2021 alle 17:18:12 UTC+1 dim...@gmail.com ha > > scritto: > > > >> On Tue, Mar 23, 2021 at 2:00 PM Mattia Villani <matt...@gmail.com> > wrote: > >>> > >>> Is is possible to find the group given the matrix presentation? > >> > >> Please be more specific. Post some Sage commands you're trying. > >> > >>> > >>> -- > >>> 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...@googlegroups.com. > >>> To view this discussion on the web visit > >> > https://groups.google.com/d/msgid/sage-support/348e69d5-b3a5-45c4-a7ec-baed9213f6dcn%40googlegroups.com > >> . > >> > > > -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/sage-support/9f462156-fa0d-496c-a97a-0fb926d51d6bn%40googlegroups.com.
