Dear All, How we can by GAP conlude all automorphism group $A_7 timesA_7$? Thanks, Sara
On 1/16/11, forum-requ...@gap-system.org <forum-requ...@gap-system.org> wrote: > Send Forum mailing list submissions to > forum@mail.gap-system.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://mail.gap-system.org/mailman/listinfo/forum > or, via email, send a message with subject or body 'help' to > forum-requ...@mail.gap-system.org > > You can reach the person managing the list at > forum-ow...@mail.gap-system.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Forum digest..." > > > Today's Topics: > > 1. Re: Changing memory allocation for GAP > (Asst. Prof. Dmitrii (Dima) Pasechnik) > 2. why zoo? (Igor Korepanov) > 3. how TzGo worked with us (Igor Korepanov) > 4. Re: why zoo? (Frank L?beck) > 5. Re: why zoo? (Asst. Prof. Dmitrii (Dima) Pasechnik) > 6. Re: Changing memory allocation for GAP (Frank L?beck) > 7. Re: how TzGo worked with us (Alexander Hulpke) > 8. Analogue of IsFFEMatrixGroup for matrix groups over ZmodnZ > (Max Horn) > 9. Re: Analogue of IsFFEMatrixGroup for matrix groups over > ZmodnZ (Alexander Hulpke) > 10. Creating block matrices (Katie Morrison) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 12 Jan 2011 18:09:05 -0800 > From: "Asst. Prof. Dmitrii (Dima) Pasechnik" <d...@ntu.edu.sg> > To: Sandeep Murthy <sandeepr.mur...@gmail.com> > Cc: GAP forum <fo...@gap-system.org> > Subject: Re: [GAP Forum] Changing memory allocation for GAP > Message-ID: > <AANLkTi=jRoG-pKmdrSjSkskLXBUPE4a6oPYbnE=bc...@mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Dear Sandeep, > it looks as if you start GAP in a wrong way. > (cause these > Error, file "-L" must exist and be readable >> Error, file "-m" must exist and be readable >> Error, file "128m" must exist and be readable >> Error, file "-o" must exist and be readable >> Error, file "512m" must exist and be readable > things are mangled details of command line arguments...) > > One way that works is to start it in a Terminal window. > Another is to use a special MacOSX application. > > Hope this helps, > Dmitrii > > On 12 January 2011 12:29, Sandeep Murthy <sandeepr.mur...@gmail.com> wrote: >> Hello. >> >> Is there a command for starting GAP from the command line to >> open with a higher memory allocation, like 256 MB, than the standard >> one? >> >> I use GAP v.4.4.12 on Mac OS Leopard. At present, when I start GAP >> I see the following: >> >> -------- >> >> Loading the library. Please be patient, this may take a while. >> GAP4, Version: 4.4.12 of 17-Dec-2008, i686-apple-darwin9.6.0-gcc >> Components: small 2.1, small2 2.0, small3 2.0, small4 1.0, small5 1.0, >> small6 1.0, small7 1.0, small8 1.0, small9 1.0, small10 0.2, >> id2 3.0, id3 2.1, id4 1.0, id5 1.0, id6 1.0, id9 1.0, id10 >> 0.1, >> trans 1.0, prim 2.1 loaded. >> Packages: AutPGrp 1.2, CTblLib 1.1.3, TomLib 1.1.4, FactInt 1.5.2, >> GAPDoc 1.2 loaded. >> Error, file "-L" must exist and be readable >> Error, file "-m" must exist and be readable >> Error, file "128m" must exist and be readable >> Error, file "-o" must exist and be readable >> Error, file "512m" must exist and be readable >> >> -------- >> >> I run search algorithms on groups of exponential complexity, and they >> are intrinsically slow. But I'm hoping that by using a higher initial >> memory allocation, for practical purposes, my programs will cover >> more of the search space than they have so far. >> >> Sincerely, Sandeep. >> >> >> _______________________________________________ >> Forum mailing list >> Forum@mail.gap-system.org >> http://mail.gap-system.org/mailman/listinfo/forum >> > > > > -- > Dmitrii Pasechnik > ----- > DISCLAIMER: Any text following this sentence does not constitute a > part of this message, and was added automatically during transmission. > > CONFIDENTIALITY: This email is intended solely for the person(s) named and > may be confidential and/or privileged. If you are not the intended > recipient, please delete it, notify us and do not copy, use, or disclose its > content. Thank you. > > Towards A Sustainable Earth: Print Only When Necessary > > > > ------------------------------ > > Message: 2 > Date: Thu, 13 Jan 2011 10:54:22 +0300 > From: Igor Korepanov <pal...@ya.ru> > To: fo...@gap-system.org > Subject: [GAP Forum] why zoo? > Message-ID: <491691294905...@web47.yandex.ru> > Content-Type: text/plain > > Just one more question: is .zoo a somehow preferred way of archiving for GAP > people? And why so if .tar.bz2 is so evidently better? > > Igor > > > > ------------------------------ > > Message: 3 > Date: Thu, 13 Jan 2011 11:22:21 +0300 > From: Igor Korepanov <pal...@ya.ru> > To: fo...@gap-system.org > Subject: [GAP Forum] how TzGo worked with us > Message-ID: <191761294906...@web4.yandex.ru> > Content-Type: text/plain > > And still one more comment: we calculated yesterday the fundamental group of > the 4-dimensional torus, which is, as everybody knows, the *abelian* group > with 4 generators. That is, the Fp Group with 4 generators and 6 relation of > type a * b * a^-1 * b^-1 . > > And all that was happily present in our GAP result, but besides that, there > was one more redundant relation which we could derive manually from 6 > others, but the TzGo algorithm apparently could not! > > We used some stuff of our own to define this fundamental group and then the > usual TzGo command to simplify it. > > Of course I've heard of undecidable problems and stuff (as I am currently > employed as a university lecturer, like many people on this forum). But this > particular problem must be decidable (here I searched Internet for a > suitable English interjection like "er?" to end my letter, but found only > some strange "Ekh-ma" http://en.wikipedia.org/wiki/Ekh_%28expression%29 ) ? > > Best wishes, > > Igor > > > > ------------------------------ > > Message: 4 > Date: Thu, 13 Jan 2011 10:37:54 +0100 > From: Frank L?beck <frank.lueb...@math.rwth-aachen.de> > To: fo...@gap-system.org > Subject: Re: [GAP Forum] why zoo? > Message-ID: <20110113093754.GA19326@beteigeuze> > Content-Type: text/plain; charset=iso-8859-1 > > On Thu, Jan 13, 2011 at 10:54:22AM +0300, Igor Korepanov wrote: >> Just one more question: is .zoo a somehow preferred way of archiving for >> GAP people? And why so if .tar.bz2 is so evidently better? > > But all of our archives are provided in .zoo, .tar.gz, .tar.bz2 and -win.zip > format. You are free to use what you like most! > > .tar.bz2 is not "evidently better", e.g. it does not unpack text files > under Windows/DOS with the native line break convention, and it is much > slower to unpack them compared to, say, .tar.gz. > > See > http://www.gap-system.org/Download/formats.html > for more details. > > Best regards, > Frank L?beck > > -- > /// Dr. Frank L?beck, Lehrstuhl D f?r Mathematik, Templergraben 64, /// > \\\ 52062 Aachen, Germany \\\ > /// E-mail: frank.lueb...@math.rwth-aachen.de /// > \\\ WWW: http://www.math.rwth-aachen.de/~Frank.Luebeck/ \\\ > > > > > ------------------------------ > > Message: 5 > Date: Thu, 13 Jan 2011 01:58:45 -0800 > From: "Asst. Prof. Dmitrii (Dima) Pasechnik" <d...@ntu.edu.sg> > To: Igor Korepanov <pal...@ya.ru> > Cc: "fo...@gap-system.org" <fo...@gap-system.org> > Subject: Re: [GAP Forum] why zoo? > Message-ID: > <AANLkTik6umPeM+FwevF26x+bwatfWBOyvW=fzppsy...@mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Igor, > .zoo is an old format, historically the first GAP was using, exclusively. > > About 10 years ago there were long discussions on this list whether one > should use other formats, and common sense prevailed, so .zoo is no longer > the only format used. > Perhaps .zoo will be retired at some point... > > On 12 January 2011 23:54, Igor Korepanov <pal...@ya.ru> wrote: >> Just one more question: is .zoo a somehow preferred way of archiving for >> GAP people? And why so if .tar.bz2 is so evidently better? >> >> Igor >> >> _______________________________________________ >> Forum mailing list >> Forum@mail.gap-system.org >> http://mail.gap-system.org/mailman/listinfo/forum >> > > > > -- > Dmitrii Pasechnik > ----- > DISCLAIMER: Any text following this sentence does not constitute a > part of this message, and was added automatically during transmission. > > CONFIDENTIALITY: This email is intended solely for the person(s) named and > may be confidential and/or privileged. If you are not the intended > recipient, please delete it, notify us and do not copy, use, or disclose its > content. Thank you. > > Towards A Sustainable Earth: Print Only When Necessary > > > > ------------------------------ > > Message: 6 > Date: Thu, 13 Jan 2011 17:41:18 +0100 > From: Frank L?beck <frank.lueb...@math.rwth-aachen.de> > To: Sandeep Murthy <sandeepr.mur...@gmail.com>, fo...@gap-system.org > Subject: Re: [GAP Forum] Changing memory allocation for GAP > Message-ID: <20110113164117.GB26842@beteigeuze> > Content-Type: text/plain; charset=iso-8859-1 > > On Wed, Jan 12, 2011 at 08:29:24PM +0000, Sandeep Murthy wrote: >> Is there a command for starting GAP from the command line to >> open with a higher memory allocation, like 256 MB, than the standard >> one? >> >> I use GAP v.4.4.12 on Mac OS Leopard. At present, when I start GAP >> I see the following: >> >> -------- >> >> Loading the library. Please be patient, this may take a while. >> GAP4, Version: 4.4.12 of 17-Dec-2008, i686-apple-darwin9.6.0-gcc >> Components: small 2.1, small2 2.0, small3 2.0, small4 1.0, small5 1.0, >> small6 1.0, small7 1.0, small8 1.0, small9 1.0, small10 0.2, >> id2 3.0, id3 2.1, id4 1.0, id5 1.0, id6 1.0, id9 1.0, id10 >> 0.1, >> trans 1.0, prim 2.1 loaded. >> Packages: AutPGrp 1.2, CTblLib 1.1.3, TomLib 1.1.4, FactInt 1.5.2, >> GAPDoc 1.2 loaded. >> Error, file "-L" must exist and be readable >> Error, file "-m" must exist and be readable >> Error, file "128m" must exist and be readable >> Error, file "-o" must exist and be readable >> Error, file "512m" must exist and be readable >> > > > Dear Sandeep Murphy, dear Forum, > > To find an explaination in the GAP documentation type > > ?command line options > > into your GAP session. If one of the arguments in your call of GAP is > a file name, then all further arguments are also interpreted as file names. > > So you should call GAP like: > gap -m 128m -o 512m [maybe more options here] file1 file2 ... > > Using the -m option with a larger amount of memory does usually not give > a big performance advantage. But using a higher value with the -o option > causes that you see a message of form > > exceeded the permitted memory (`-o' command line option) at > [...] > brk> > > later than with the default value. (You can type 'return;' at that > brk-prompt, then GAP doubles the value of the -o option.) > Nevertheless, it does not make sense to specify with -o more memory than > your GAP job has available as physical memory. > > With best regards, > Frank L?beck > > -- > /// Dr. Frank L?beck, Lehrstuhl D f?r Mathematik, Templergraben 64, /// > \\\ 52062 Aachen, Germany \\\ > /// E-mail: frank.lueb...@math.rwth-aachen.de /// > \\\ WWW: http://www.math.rwth-aachen.de/~Frank.Luebeck/ \\\ > > > > > ------------------------------ > > Message: 7 > Date: Thu, 13 Jan 2011 10:20:17 -0700 > From: Alexander Hulpke <hul...@math.colostate.edu> > To: gap forum <fo...@gap-system.org> > Subject: Re: [GAP Forum] how TzGo worked with us > Message-ID: <3196fba1-3829-4234-a59d-9bc51e350...@math.colostate.edu> > Content-Type: text/plain; charset=us-ascii > > > > Dear Forum, > > On Jan 13, 2011, at 1/13/11 1:22, Igor Korepanov wrote: > >> And still one more comment: we calculated yesterday the fundamental group >> of the 4-dimensional torus, which is, as everybody knows, the *abelian* >> group with 4 generators. That is, the Fp Group with 4 generators and 6 >> relation of type a * b * a^-1 * b^-1 . >> >> And all that was happily present in our GAP result, but besides that, >> there was one more redundant relation which we could derive manually from >> 6 others, but the TzGo algorithm apparently could not! > > TzGo (the Tietze transformations command) uses a couple of heuristics, based > on length criteria, to shorten a presentation, in particular if it was > obtained from rewriting to a subgroup. It does not aim to do a systematic > search for all redundancies. The primary aim is to get a presentation > shorter with a moderate amount of effort, not to get an irredundant > presentation or cover the largest possible class of decidable problems. It > is clearly not optimal, but adding further attempts might cause an overall > slowdown in other situations. > > Thus I'm not surprised that thinking (or even other algorithms that would be > willing to devote more time) can produce better results in particular > situations. > > Best wishes, > > Alexander Hulpke > > > > > -- Colorado State University, Department of Mathematics, > Weber Building, 1874 Campus Delivery, Fort Collins, CO 80523-1874, USA > email: hul...@math.colostate.edu, Phone: ++1-970-4914288 > http://www.math.colostate.edu/~hulpke > > > > > > > ------------------------------ > > Message: 8 > Date: Fri, 14 Jan 2011 15:24:16 +0100 > From: Max Horn <m...@quendi.de> > To: GAP Forum <fo...@gap-system.org> > Subject: [GAP Forum] Analogue of IsFFEMatrixGroup for matrix groups > over ZmodnZ > Message-ID: <01d99a4d-2e0a-46d6-bca3-8b8d4163a...@quendi.de> > Content-Type: text/plain; charset=us-ascii > > Dear GAP forum > > is there an analogue for IsFFEMatrixGroup and FieldOfMatrixGroup for groups > over ZmodnZ ? Something like IsZmodnZMatrixGroup and RingOfMatrixGroup ? I > didn't find anything like that. If it doesn't exist, how would I best go > about adding those? > > Background: I'd like to install my own methods for e.g. NiceMonomorphism for > matrix groups over ZmodnZ. To illustrate why: for GL(3, Z/36Z), GAP > currently finds a perm rep on 39312 points, my code finds one on 758 points > (it doesn't do anything fancy or new, mind you) > > For now, I just "manually" use SetNiceMonomorphism on my groups, but I > thought it would be kinda nice to properly hook this into GAP (so that maybe > it could even be integrated in a package or GAP itself one day). > > > Cheers, > Max > > > > > ------------------------------ > > Message: 9 > Date: Fri, 14 Jan 2011 10:03:32 -0700 > From: Alexander Hulpke <hul...@math.colostate.edu> > To: Max Horn <m...@quendi.de> > Cc: GAP Forum <fo...@gap-system.org> > Subject: Re: [GAP Forum] Analogue of IsFFEMatrixGroup for matrix > groups over ZmodnZ > Message-ID: <965b2533-1ac7-486e-acaa-32bd16bcf...@math.colostate.edu> > Content-Type: text/plain; charset=us-ascii > > > > Dear Forum, > > On Jan 14, 2011, at 1/14/11 7:24, Max Horn wrote: > >> is there an analogue for IsFFEMatrixGroup and FieldOfMatrixGroup for >> groups over ZmodnZ ? Something like IsZmodnZMatrixGroup and >> RingOfMatrixGroup ? I didn't find anything like that. If it doesn't exist, >> how would I best go about adding those? > > Assuming you want to catch the case for nonprime n, the equivalent for > IsFFEMatrixGroup would be > IsZmodnZObjNonprimeCollCollColl and IsMatrixGroup > > To get the underlying ring, you could use > DefaultRing(Flat(GeneratorsOfGroup(g))); > > Best wishes, > > Alexander Hulpke > > > > > > > > ------------------------------ > > Message: 10 > Date: Sun, 16 Jan 2011 22:21:10 -0600 > From: Katie Morrison <kmorr...@gmail.com> > To: fo...@gap-system.org > Subject: [GAP Forum] Creating block matrices > Message-ID: > <AANLkTikx8fOUPG=ob1FxdQCpXikqYnk=-bacpcslj...@mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > Hi all, I was wondering if there's an efficient way to create the subgroup > of GL(2n, q) consisting of block matrices of the form: > [A 0 > B C] > where A and C are in GL(n,q) and B is in M(n,q) (i.e. B is an arbitrary nxn > matrix). Thanks for the help. > > Katie > > > ------------------------------ > > _______________________________________________ > Forum mailing list > Forum@mail.gap-system.org > http://mail.gap-system.org/mailman/listinfo/forum > > > End of Forum Digest, Vol 86, Issue 6 > ************************************ > _______________________________________________ Forum mailing list Forum@mail.gap-system.org http://mail.gap-system.org/mailman/listinfo/forum
