Re: [sage-devel] Bug in .subgroup?
On Thu, Apr 4, 2024 at 11:07 AM Dima Pasechnik wrote: > > 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 ? yes, indeed, it came from https://github.com/sagemath/sage/pull/36986 I've opened https://github.com/sagemath/sage/issues/37744 > > On Thu, Apr 4, 2024 at 10:24 AM 'B. L.' via sage-devel > 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/CAAWYfq17xtj%2BroU9QWBMF6DV4HmPRg4EmgpXnLRzsad%2BZ8k6MA%40mail.gmail.com.
Re: [sage-devel] Bug in .subgroup?
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 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.
[sage-devel] Bug in .subgroup?
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.