> < ^ Date: Thu, 20 Oct 1994 23:03:00 +0100
> < ^ From: Dmitrii Pasechnik <d.pasechnik@twi.tudelft.nl >
< ^ Subject: Re: Size of subgroup generated by classes

Given a charatcer table record, I'd like to calculate the size of the
subgroup generated by a list of classes. Is this possible in GAP?
Actually I am not sure if this is theoretically possible, so perhaps
I should ask if the character table record (and in particular the power
maps) contain enough information to do this. Thanks.

Jacob Hirbawi <JcbHrb@CERF.net>

I'd guess that all the information needed is already in.
There is a function ClassMultCoeffCharTable(tbl,c1,c2,c3),
it returns the number of pairs (x,y) of elements of G
such that x\in c1, y\in c2, and xy is a fixed element
of c3.

So one can start with a given subset of classes and repeatedly
apply this function to find all the classes which get involved.
Then it remains to add up their sizes.

( Since it appears to be practically possible, it should also
be possible theoretically. :-) )

Dima Pasechnik,

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