[GAP Forum] Testing action of automorphisms on groups

[Stephen Linton]

Ah I see. Your group B is made using PcGroupAutPcGroup. This essentially forgets that the group is an automorphism group and simply computes an isomorphic PC Group ( at least for the soluble part). If you want to work with the automorphisms as such, you either need to work directly in the AutomorphismGroup, or keep track of the explicit isomorphism between that group and a PC group.

     Steve



From: Siddhartha Sarkar <siddhartha18 at gmail.com>
Date: Sunday, 23 February 2020 at 11:39
To: Stephen Linton <sl4 at st-andrews.ac.uk>
Cc: GAP Forum <forum at gap-system.org>
Subject: Re: Testing action of automorphisms on groups

Dear Stephen,

Thanks. It still shows an error.

Siddhartha




gap> p:=Image(a1,x1);

Error, usage: Image(<map>), Image(<map>,<elm>), Image(<map>,<coll>) at /Users/sidhu/Desktop/GAP/gap-4.10.2/lib/mapping.gi:198<http://mapping.gi:198> called from

<function "Image">( <arguments> )

 called from read-eval loop at *stdin*:19

you can 'quit;' to quit to outer loop, or

you can 'return;' to continue

brk> return;

Error, Function call: <func> must return a value

not in any function at *stdin*:19