As far as I see, your group u is a 2-step nilpotent group of order 2^14 * 3, which suggests that it has quite a lot of normal subgroups. So you may need at least some patience, even if you convert the group into a pc group first in order to speed up the computation.
Best regards, Stefan Kohl ________________________________ From: Surinder Kaur <surinder.k...@iitrpr.ac.in> Sent: Saturday, February 9, 2019 8:43:26 AM To: forum@gap-system.org Subject: [GAP Forum] Normal subgroups of unit group of group algebra FD_8, for the field F with 4 elements Dear all Is there any way to get all the normal subgroups of the normalized unit group V(FD_8), where FD_8 is the group ring of the dihedral group D_8 and F is the field with 4 elements. I tried the following straight forward way but it's not working. g:=DihedralGroup(8);; f:=GF(4);; fg:=GroupRing(f,g);; e:=Identity(fg);; u:=Units(fg);; h:=NormalSubgroups(u);; Print(h, "\n"); -- *Regards* *Surinder Kaur* *Research scholar * *Department of Mathematics * *IIT Ropar* _______________________________________________ Forum mailing list Forum@gap-system.org https://mail.gap-system.org/mailman/listinfo/forum _______________________________________________ Forum mailing list Forum@gap-system.org https://mail.gap-system.org/mailman/listinfo/forum