[sage-devel] Re: Matrix groups are not uniquely represented, why?
I believe the matrix and permutation groups are quite old code, so UniqueRepresentation may not have been available at that time. The permutation group code does need updating; in particular, it is still an old-style parent: sage: S.__class__.__mro__ (, , , , , , , , , , , , ... (Side note: We also should not be importing things like PermutationGroup_generic and PermutationGroupMorphism_id into the global namespace.) I don't see a reason off-hand why these should not be UniqueRepresentation subclasses. Best, Travis -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Sage developer co-authors article on women's representation in subfields
Unfortunately a paywall, but very interesting data and analysis relevant to mathematical software communities too - plus, Sage developer and co-author Ursula Whitcher of Math Reviews gives a shout-out to SageMath in the author bio :) https://link.springer.com/article/10.1007%2Fs00283-017-9761-7 -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
Re: [sage-devel] Sage developer co-authors article on women's representation in subfields
On 5/25/2018 11:02 AM, kcrisman wrote: Unfortunately a paywall, but very interesting data and analysis relevant to mathematical software communities too - plus, Sage developer and co-author Ursula Whitcher of Math Reviews gives a shout-out to SageMath in the author bio :) https://link.springer.com/article/10.1007%2Fs00283-017-9761-7 Thank you! There's a preprint version on the arXiv, naturally: https://arxiv.org/abs/1509.07824 (And I did a bunch of the data analysis in python, using skills I learned from Sage development!) UAW -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
Re: [sage-devel] Sage developer co-authors article on women's representation in subfields
On Fri, May 25, 2018 at 8:02 AM, kcrisman wrote: > Unfortunately a paywall, but very interesting data and analysis relevant to > mathematical software communities too - plus, Sage developer and co-author > Ursula Whitcher of Math Reviews gives a shout-out to SageMath in the author > bio :) > https://link.springer.com/article/10.1007%2Fs00283-017-9761-7 I can't / wont read it because of the paywall. Can you copy/paste the paragraph that mentions Sage? (or screenshot it). Fair use of small excerpts... > > -- > 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 post to this group, send email to sage-devel@googlegroups.com. > Visit this group at https://groups.google.com/group/sage-devel. > For more options, visit https://groups.google.com/d/optout. -- William (http://wstein.org) -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Re: Matrix groups are not uniquely represented, why?
On Friday, May 25, 2018 at 1:00:22 AM UTC-7, Travis Scrimshaw wrote: > > I believe the matrix and permutation groups are quite old code, so > UniqueRepresentation may not have been available at that time. The > permutation group code does need updating; in particular, it is still an > old-style parent: > > sage: S.__class__.__mro__ > ( 'sage.groups.perm_gps.permgroup_named.SymmetricGroup_with_category'>, > , > , > , > , > , > , > , > , > , > , > , > ... > > (Side note: We also should not be importing things like > PermutationGroup_generic and PermutationGroupMorphism_id into the global > namespace.) > > I don't see a reason off-hand why these should not be UniqueRepresentation > subclasses. > There is a very good reason why they should NOT'. Equality between subgroups is not uniquely determined by the construction parameters. It's part of the API of UniqueRepresentation that equality is identity on them. Also, UniqueRepresentation objects make it much harder to write predictable code: because they're global objects they really MUST be immutable. No cheating! That's often quite inconvenient. Also, the processing of the construction parameters is possibly more expensive than the construction itself, so they may degrade performance. Furthermore, they have proven time and again to be very prone to memory leaks, to the point where I'd now work on the assumption that if you change an object to UniqueRepresentation, you're introducing memory leaks various places. -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Book Review of Stein book
Less relevant, but still ... Also probably behind a paywall ... anyway, this is a review of Barry Mazur and William Stein's book on the Riemann Hypothesis by someone who knows something about writing good books about analytic number theory and representation theory. No Sage in the review but see the Github repo for the book https://github.com/williamstein/rh for the worksheets/code that generated the illustrations. https://www.tandfonline.com/doi/full/10.1080/00029890.2018.1438005 -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
Re: [sage-devel] Book Review of Stein book
On Fri, May 25, 2018 at 10:47 AM, kcrisman wrote: > Less relevant, but still ... Also probably behind a paywall ... anyway, this > is a review of Barry Mazur and William Stein's book on the Riemann > Hypothesis by someone who knows something about writing good books about > analytic number theory and representation theory. No Sage in the review but > see the Github repo for the book https://github.com/williamstein/rh for the > worksheets/code that generated the illustrations. > > https://www.tandfonline.com/doi/full/10.1080/00029890.2018.1438005 I'm giving a talk in two weeks (in Boston) on "the experience of writing and publishing that book". If anybody has any comments or questions, let me know, since it'll help me prepare my talk :-). William > > -- > 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 post to this group, send email to sage-devel@googlegroups.com. > Visit this group at https://groups.google.com/group/sage-devel. > For more options, visit https://groups.google.com/d/optout. -- William (http://wstein.org) -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
Re: [sage-devel] Book Review of Stein book
On 25 May 2018 at 18:47, kcrisman wrote: > Less relevant, but still ... Also probably behind a paywall ... anyway, > this is a review of Barry Mazur and William Stein's book on the Riemann > Hypothesis by someone who knows something about writing good books about > analytic number theory and representation theory. No Sage in the review > but see the Github repo for the book https://github.com/williamstein/rh > for the worksheets/code that generated the illustrations. > > https://www.tandfonline.com/doi/full/10.1080/00029890.2018.1438005 > Yes, there is a paywall for all but the first page of the review. (They offered to let me have 24 hours access to the review for £35 which is rather more than the entire book costs). Surprising that Avner Ash seems to have confused the BSD conjecture (unproved and a Millennium problem) with Fermat (proved and not). John > > -- > 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 post to this group, send email to sage-devel@googlegroups.com. > Visit this group at https://groups.google.com/group/sage-devel. > For more options, visit https://groups.google.com/d/optout. > -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Re: Matrix groups are not uniquely represented, why?
Hi! On 2018-05-25, Nils Bruin wrote: >> I don't see a reason off-hand why these should not be UniqueRepresentation >> subclasses. >> > > There is a very good reason why they should NOT'. Equality between > subgroups is not uniquely determined by the construction parameters. It's > part of the API of UniqueRepresentation that equality is identity on them. But they could still be CachedRepresentation. Then, if the same subgroup is given by the same generators, it is identical, but if the same subgroup is given by different generators, it is just equal but not identical. Best regards, Simon -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Re: Matrix groups are not uniquely represented, why?
On Friday, May 25, 2018 at 12:17:35 PM UTC-7, Simon King wrote: > > But they could still be CachedRepresentation. Then, if the same subgroup > is given by the same generators, it is identical, but if the same > subgroup is given by different generators, it is just equal but not > identical. > > But before doing so, you would need to show that in common scenarios it produces a benefit. It has three significant draw-backs: - you'd slow down the creation of matrix groups in general, because you're requiring the system to first go and look if there already is an object like it. - because the object you get *may* be shared with other code, you're at the mercy of that other code to not mutate it. (and you have to behave yourself too) - it would likely introduce memory leaks (because it's the CachedRepresentation part of UniqueRepresentation that makes these leaks likely). -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
[sage-devel] Re: Matrix groups are not uniquely represented, why?
MatrixGroups are immutable and their comparison is by checking the generators (and not isomorphism), which are essentially the construction parameters (in reality, they are the corresponding GAP group). For permutation groups, the equality seems to be isomorphism. So there is no problem for MatrixGroups being UniqueRepresentation in terms of behavior. Best, Travis On Saturday, May 26, 2018 at 5:53:15 AM UTC+10, Nils Bruin wrote: > > > > On Friday, May 25, 2018 at 12:17:35 PM UTC-7, Simon King wrote: >> >> But they could still be CachedRepresentation. Then, if the same subgroup >> is given by the same generators, it is identical, but if the same >> subgroup is given by different generators, it is just equal but not >> identical. >> >> But before doing so, you would need to show that in common scenarios it > produces a benefit. It has three significant draw-backs: > - you'd slow down the creation of matrix groups in general, because > you're requiring the system to first go and look if there already is an > object like it. > - because the object you get *may* be shared with other code, you're at > the mercy of that other code to not mutate it. (and you have to behave > yourself too) > - it would likely introduce memory leaks (because it's the > CachedRepresentation part of UniqueRepresentation that makes these leaks > likely). > > -- 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 post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
