Yes, it's surely a bug; this example gives |gg|=2^27 (wow!), or a smaller one:
sage: g=AbelianGroup([2,2]) sage: gg=g.subgroup(g.list()) sage: gg.cardinality().factor() # what? 2^3 sage: g.cardinality().factor() 2^2 Maybe related to https://github.com/sagemath/sage/pull/36986 ? On Thu, Apr 4, 2024 at 10:24 AM 'B. L.' via sage-devel <sage-devel@googlegroups.com> wrote: > > Hello, > to me it seems that with 10.3 there might be a bug in ".subgroup", see > example below. The subgroup cardinality is wrong and the equality test of the > group and the subgroup generated by all group elements yields "False". In > previous versionls of SAGE this worked as expected. > Can anybody help? > Thanks and kind regards, > Barbara > > > sage: g = AbelianGroup([4, 4]) > sage: gg = g.subgroup(g.list()) > sage: g > Multiplicative Abelian group isomorphic to C4 x C4 > sage: gg > Multiplicative Abelian subgroup isomorphic to C4 x C4 generated by {f1, f1^2, > f1^3, f0, f0*f1, f0*f1^2, f0*f1^3, f0^2, f0^2*f1, f0^2*f1^2, f0^2*f1^3, f0^3, > f0^3*f1, f0^3*f1^2, f0^3*f1^3} > sage: g.cardinality() > 16 > sage: gg.cardinality() > 134217728 > sage: g==gg > False > > -- > 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 on the web visit > https://groups.google.com/d/msgid/sage-devel/55ecbb00-3927-4339-8cb3-f68347358446n%40googlegroups.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 on the web visit https://groups.google.com/d/msgid/sage-devel/CAAWYfq12wP_ANzFv7RqPVrw1CTDRa8MuU0MA%2BXBXS6RnUGSKHQ%40mail.gmail.com.
