[GAP Forum] how to recognise a group?

[Robert Morse]

You can create a file with GAP commands and read them into GAP with
the Read command.

If you put

M := [ [ 1, 2, 3, 4, 5 ], [ 2, 3, 4, 5, 1 ], [ 3, 4, 5, 1, 2 ], [ 4,
5, 1, 2, 3 ], [ 5, 1, 2, 3, 4 ] ];

in a file "table.g" and at the GAP command prompt

gap> Read("table.g");
gap> M;
[ [ 1, 2, 3, 4, 5 ], [ 2, 3, 4, 5, 1 ], [ 3, 4, 5, 1, 2 ], [ 4, 5, 1,
2, 3 ], [ 5, 1, 2, 3, 4 ] ]

you see the variable is assigned as needed.

I am assuming that you are generating the tables using some program.
If so make sure it is formatted as a list of lists that GAP can use.

Also look at

http://www.gap-system.org/Manuals/doc/ref/chap9.html#X8373AC6B7D5F9167

for more information on the GAP read command.

Robert

On Fri, Aug 17, 2012 at 8:56 AM, R.E. Boss <r.e.boss at planet.nl> wrote:
> Thanks for the reply.
> Problem becomes: how do I enter a multiplication table of 2304 = 48^2 elements into GAP?
> Is there some read facility?
> Preparing a list of 48 lists of 48 elements is not the problem, entering by hand is quite another story.
>
>
> R.E. Boss
>
>
>> -----Oorspronkelijk bericht-----
>> Van: rfmorse at gmail.com [mailto:rfmorse at gmail.com] Namens Robert Morse
>> Verzonden: donderdag 16 augustus 2012 14:51
>> Aan: R.E. Boss
>> CC: forum at gap-system.org
>> Onderwerp: Re: [GAP Forum] how to recognise a group?
>>
>> In my example the table M is the cyclic group.
>>
>> Given the multiplication table say M do the following:
>>
>> Form the group using the multiplication table:
>>
>> gap> G := GroupByMultiplicationTable(M);
>> <group of size 48 with 48 generators>
>>
>> Ask for some structural information to get an idea what the group is:
>>
>> gap> StructureDescription(G);
>> "C48"
>>
>> Robert F. Morse
>>
>> On Tue, Aug 14, 2012 at 1:49 PM, R.E. Boss <r.e.boss at planet.nl> wrote:
>> > Hello,
>> >
>> >
>> >
>> > I'm new to Gap and using it for a couple of days only and would like to have the next question answered.
>> >
>> > If I have a multiplication table of a (small) group, how can I determine which group it is?
>> >
>> > The actual table I have is for group of 48 elements.
>> >
>> >
>> >
>> > R.E. Boss
>> >
>> >
>> >
>> >
>> >
>> > _______________________________________________
>> > Forum mailing list
>> > Forum at mail.gap-system.org
>> > http://mail.gap-system.org/mailman/listinfo/forum
>