On Mon, Apr 17, 2023 at 7:40 AM Tracy Hall <h.tr...@gmail.com> wrote:
> (error present at least from SageMath 8.2 until SageMath 9.8) > in 10.0.beta9 one gets sage: BG = BraidGroup(5) sage: b = BG([3, 3, 4, 3, 3, 2, 1, 4, 3, 2]); b s2^2*s3*s2^2*s1*s0*s3*s2*s1 sage: b.centralizer() double free or corruption (out) (and then it hangs) > > On Monday, April 17, 2023 at 12:36:41 AM UTC-6 Tracy Hall wrote: > >> Attempting to calculate the centralizer of a particular element of the >> braid group on 5 strands causes a segmentation fault. >> >> sage: BG = BraidGroup(5); BG >> Braid group on 5 strands >> >> sage: b = BG([3, 3, 4, 3, 3, 2, 1, 4, 3, 2]); b >> s2^2*s3*s2^2*s1*s0*s3*s2*s1 >> >> sage: b.left_normal_form() >> (1, s2*s3*s2, s2*s1*s0*s3*s2*s1*s0) >> >> sage: b.ultra_summit_set() >> [[s0*s1*s0*s2*s1*s0*s3*s2*s1*s0]] >> >> sage: b.is_pseudoanosov() >> False >> >> sage: b.centralizer() >> >> --------------------------------------------------------------------------- >> SignalError Traceback (most recent call >> last) >> Cell In [7], line 1 >> ----> 1 b.centralizer() >> File /ext/sage/9.8/src/sage/groups/braid.py:1546, in >> Braid.centralizer(self) >> 1534 def centralizer(self): >> 1535 """ >> 1536 Return a list of generators of the centralizer of the braid. >> 1537 >> (...) >> 1544 >> 1545 """ >> -> 1546 l = centralizer(self) >> 1547 B = self.parent() >> 1548 return [B._element_from_libbraiding(b) for b in l] >> File /ext/sage/9.8/src/sage/libs/braiding.pyx:233, in >> sage.libs.braiding.centralizer() >> 231 return [[[0], [i+1, nstrands - i -1]] for i in >> range(nstrands//2-1)] + [[[0], [nstrands//2]]] >> 232 l = braid.Tietze() >> --> 233 sig_on() >> 234 cdef list[list[list[int]]] rop = CentralizerGenerators(nstrands, >> l) >> 235 sig_off() >> SignalError: Segmentation fault >> > -- > 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/be9455fb-ab03-43bb-93f2-dd3a2c43186bn%40googlegroups.com > <https://groups.google.com/d/msgid/sage-support/be9455fb-ab03-43bb-93f2-dd3a2c43186bn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- 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/CAAWYfq0yVL9%3DsxkB5ikaNyfEJPbiFZEBq0Shxy2RVHypYua4Jw%40mail.gmail.com.
