> < ^ From:

< ^ Subject:

Dear Forum,

>> 2. An alternative is to use the library of perfect groups in GAP.

>

>That's a good method, but how do you know that the

>group in question is perfect?

Roughly speaking, there is no abelian group "on top"...

One can, for instance, rule out, on case-by-case basis,

all the possibilities for the commutator subgroup to be

a proper normal subgroup. There are not that many of them.

>> 3. A third possibility is the construction of the semidirect

>> product as a group of 4 by 4 matrices over the field with

>> 5 elements.

>

>I can't see why this construction gives the group in question.

> Can you say a bit

>more or give some references about that?

The group in question is an index two subgroup in the point

stabilizer of Sp_4(5) acting naturally on its 4-dim. module.

See e.g. Atlas of Finite Groups by Conway et al.

I posted 4x4-matrices that generate it to the Forum, but the message

apparently got lost somewhere...

Best wishes,

Dmitrii Pasechnik

e-mail: dima@cs.uu.nl

http://www.cs.uu.nl/staff/dima.html/

Miles-Receive-Header: reply

> < [top]