On Wed, Mar 25, 2009 at 12:43:20AM +0800, Asst. Prof. Dmitrii (Dima) Pasechnik wrote: > Dear Andreas, > > PSL is not a matrix group, it is an action of SL on the projective > space, i.e. on the 1-dimensional subspaces. It is the quotient of SL > over the centre, which consists of scalar matrices. Then indeed, when > q=2, it is isomorphic to SL, so you can work with e.g. > SpecialLinearGroup( 2, 2 ) directly. > (You can certainly do this for bigger q too, but you have to keep in > mind that yoiu work with a preimage of the homomorphism)
However it is certainly possible to represent PGL(K,n) and PSL(K,n) as a matrix group in GL(K,n^2) as the image of the action of GL(K,n) on End(K^n) by conjugacy and identifying End(K^n) with K^(n^2). This should be easily done in GAP. Cheers, Bill. _______________________________________________ Forum mailing list [email protected] http://mail.gap-system.org/mailman/listinfo/forum
