[GAP Forum] IsomorphismTypeFiniteSimpleGroup results in an error.

Alexander Konovalov alexk at mcs.st-andrews.ac.uk
Mon Sep 15 18:46:30 BST 2014


On 15 Sep 2014, at 12:41, buynnnmmm1 at yahoo.co.jp wrote:

> Thank you very much for e-mail immediately.
> Thank you very much for your help.
> I was sure that even here can do it.

You're welcome! Glad that this was helpful.
> 
> gap> s8:=Group((1,2),(1,2,3,4,5,6,7,8));
> Group([ (1,2), (1,2,3,4,5,6,7,8) ])
> gap> a8:=CommutatorSubgroup(s8,s8);
> Group([ (1,3,2), (2,4,3), (3,5,4), (4,6,5), (5,7,6), (6,8,7) ])
> gap> elab:= Group( (1,2)(3,4)(5,6)(7,8), (1,3)(2,4)(5,7)(6,8),  (1,5)(2,6)(3,7)(4,8));
> Group([ (1,2)(3,4)(5,6)(7,8), (1,3)(2,4)(5,7)(6,8), (1,5)(2,6)(3,7)(4,8) ])
> gap> norm:= Normalizer( a8, elab );;
> gap> hom:=NaturalHomomorphismByNormalSubgroup( norm , elab );
> <action epimorphism>
> gap> f := Image( hom );
> Group([ (), (), (), (4,5)(6,7), (4,6)(5,7), (2,3)(6,7), (2,4)(3,5), (1,2)(5,6) ])
> gap> IsomorphismTypeInfoFiniteSimpleGroup( f );
> rec( name := "A(1,7) = L(2,7) ~ B(1,7) = O(3,7) ~ C(1,7) = S(2,7) ~ 2A(1,7) = U(2,7) ~ A(2,2) = L(3,2)", parameter := [ 2, 7 ], 
>   series := "L" )
> 
> I've read http://www.gap-system.org/Manuals/doc/ref/chap77.html.
> Then, Http://www.math.niu.edu/help/math/gap4/ref/CHAP036.htm was hit when I net doing a keyword search for "IsomorphismTypeFiniteSimpleGroup".

This NIU-hosted copy of GAP manuals refers to some version of GAP that was around in 2000. At that time it was not uncommon to host mirrors of GAP distribution, and many places were also serving a copy GAP documentation for local users to help with slow connections or internet blackouts. Many places stopped doing this when the network became faster and reliable, so my conjecture would be that most of the copies of GAP manuals that may be found outside the main GAP website are actually outdated (until recently, GAP website still provided HTML version of GAP 3 manuals, and now they are only available in a tar.gz archive to prevent search engines pointing to GAP 3 manuals which may cause even more confusion trying them in GAP 4).

Anyhow, you do not need to search for the GAP Documentation in the Internet, since it is included in your GAP installation, and GAP provides a command-line functionality to search in it using the ? (question mark) operator or ?? (double question mark). For example, you might have tried to find the exact match with '?':

gap> ?IsomorphismTypeFiniteSimpleGroup    
Help: no matching entry found

and then decide to try with '??' to find all search index entries that contain a given substring, like here:


gap> ??IsomorphismType                 
Help: several entries match this topic - type ?2 to get match [2]

[1] Reference: IsomorphismTypeInfoFiniteSimpleGroup
[2] Reference: IsomorphismTypeInfoFiniteSimpleGroup (for a group)
[3] Reference: IsomorphismTypeInfoFiniteSimpleGroup (for a group order)
[4] Reference: IsomorphismTypeInfoFiniteSimpleGroup (for a character table)


or like here:


gap> ??FiniteSimpleGroup               
Help: several entries match this topic - type ?2 to get match [2]

[1] Reference: IsomorphismTypeInfoFiniteSimpleGroup
[2] Reference: IsomorphismTypeInfoFiniteSimpleGroup (for a group)
[3] Reference: IsomorphismTypeInfoFiniteSimpleGroup (for a group order)
[4] Reference: IsomorphismTypeInfoFiniteSimpleGroup (for a character table)


Now you may type ?1 to see the 1st entry, etc. Also, the command SetHelpViewer (you may try to see its description by entering ?SetHelpViewer) can be used to use nicer display methods for the online help (for example, I normally set the viewer to my preferred HTML browser). 

Furthermore, if you wish to use the external search engine, then the GAP website offers its own search tool at http://www.gap-system.org/search.html. Using it, you may e.g. search only in Gap Forum Archives or in the Gap 4 Manual. Also, you may ask Google to search only within the GAP website by adding "site:www.gap-system.org" in the search form after your search input.

> I was Written in the document with the "GAP 4 manual February 2000". 
> It seems there was IsomorphismTypeInfoFiniteSimpleGroup function in GAP4 of the old version.
> 
> This document, because it is updated on 2014/8/16 recently,
 
Could this be a typo? I can't read it, but page two of the PDF file has timestamp 02/08/16 and this can't be 2016 yet. And also http://sci.kj.yamagata-u.ac.jp/~waki/jpn/gap_docs/ says this file is from 2003. 

We could add a link to this document to the page http://www.gap-system.org/Doc/Teaching/teaching.html (which already lists another teaching material in Japanese) if someone will suggest a description. It seems that most of examples still will work.

> I think the document author and not using "GAPDoc package". 

I think too - GAPDoc-based manuals have their recognisable style. Using Unicode fonts, in principle one should be able to create GAPDoc-based documents in Japanese.

Best wishes
Alexander



> I leave the mail also "GAPDoc package" to the author.
> 
> 
> Thank you very much for your help!
> 
> P.S.
> I resend same e-mail because I've forgotten cc column of mail (forum at gap-system.org).
> 
>                    buynnnmmm1
> 
> 
> 
> 
> ----- Original Message -----
>> From: Alexander Konovalov <alexk at mcs.st-andrews.ac.uk>
>> To: buynnnmmm1 at yahoo.co.jp
>> Cc: "forum at gap-system.org" <forum at gap-system.org>
>> Date: 2014/9/15, Mon 18:25
>> Subject: Re: [GAP Forum] IsomorphismTypeFiniteSimpleGroup results in an error.
>> 
>> Hello,
>> 
>> The correct name of this function is IsomorphismTypeInfoFiniteSimpleGroup. Using 
>> the input from the question, it produces the expected result:
>> 
>> gap> IsomorphismTypeInfoFiniteSimpleGroup( f );
>> rec( name := "A(1,7) = L(2,7) ~ B(1,7) = O(3,7) ~ C(1,7) = S(2,7) ~ 2A(1,7) 
>> = U(2,7) ~ A(2,2) = L(3,2)", parameter := [ 2, 7 ], series := "L" 
>> )
>> gap> 
>> 
>> I don't know for sure if this is a typo or the function was renamed in GAP, 
>> but it could be the former - I can see IsomorphismTypeInfoFiniteSimpleGroup 
>> mentions dated back to 2003. It seems that the document you mention is dated 
>> 2002 and refers to GAP 4.2, so it is plausible that some examples are not 
>> reproducible and should be adapted to GAP 4.7. Most of such cases are covered in 
>> the Chapter "Replaced and Removed Command Names" of the GAP Reference 
>> manual (http://www.gap-system.org/Manuals/doc/ref/chap77.html), and in doubt 
>> please just ask.
>> 
>> Best wishes
>> Alexander
>> 
>> P.S. It should be possible to produce GAP teaching materials in various 
>> languages using GAPDoc package, and run automated tests of their examples to 
>> check that they all still work with new versions of GAP. This will simplify 
>> their maintenance and their upgrading after major GAP releases.
>> 
>> 
>> On 15 Sep 2014, at 05:06, buynnnmmm1 at yahoo.co.jp wrote:
>> 
>>> 
>>> 
>>> Hello.
>>> It is an error to try to do in the Gap4.7.5 
>> IsomorphismTypeFiniteSimpleGroup of P.27 of 
>> http://sci.kj.yamagata-u.ac.jp/~waki/jpn/gap_docs/take_gap.pdf. 
>>> 
>>> gap> s8:=Group((1,2),(1,2,3,4,5,6,7,8));
>>> Group([ (1,2), (1,2,3,4,5,6,7,8) ])
>>> gap> a8:=CommutatorSubgroup(s8,s8);
>>> Group([ (1,3,2), (2,4,3), (2,3)(4,5), (2,4,6,5,3), (2,5,3)(4,7,6), 
>> (2,3)(5,6,8,7) ])
>>> gap> elab:= Group( (1,2)(3,4)(5,6)(7,8), (1,3)(2,4)(5,7)(6,8),  
>> (1,5)(2,6)(3,7)(4,8));
>>> Group([ (1,2)(3,4)(5,6)(7,8), (1,3)(2,4)(5,7)(6,8), (1,5)(2,6)(3,7)(4,8) ])
>>> gap> norm:= Normalizer( a8, elab );;
>>> gap> hom:=NaturalHomomorphismByNormalSubgroup( norm , elab );
>>> <action epimorphism>
>>> gap> f := Image( hom );
>>> Group([ (), (), (), (4,5)(6,7), (4,6)(5,7), (2,3)(6,7), (2,4)(3,5), 
>> (1,2)(5,6) ])
>>> gap> IsomorphismTypeFiniteSimpleGroup( f );
>>> Error, Variable: 'IsomorphismTypeFiniteSimpleGroup' must have a 
>> value
>>> not in any function at line 16 of *stdin*
>>> 
>>> 
>>> However, I should be able to get the following output: In P.27 of this PDF 
>> file.
>>> 
>>> gap> IsomorphismTypeFiniteSimpleGroup( f );
>>> rec( series := "L", parameter := [ 2, 7 ],
>>> name := "A(1,7) = L(2,7) ~ B(1,7) = O(3,7) ~ C(1,7) = S(2,7) ~
>>> 2A(1,7) = U(2\
>>> ,7) ~ A(2,2) = L(3,2)" )
>>> 
>>> 
>>> Could you tell me how to solve this problem? 
>>> How to use or probably been changed in accordance with the version up? 
>>> Or bug or probably are mixedin Gap version up?
>>> 
>>> 
>>>                                    buynnnmmm1
>>> 
>>> _______________________________________________
>>> Forum mailing list
>>> Forum at mail.gap-system.org
>>> http://mail.gap-system.org/mailman/listinfo/forum
>> 




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