[GAP Forum] IsMinimalNonmonomial(AlternatingGroup(5));

[Sam Tertooy]

Dear Bill,

It seems like there is currently no method installed for non-solvable groups. Assuming you're not too worried about performance, you could install a naive method for non-solvable groups with the code below (someone please correct me if I made a mistake anywhere):

InstallMethod(
	IsMinimalNonmonomial,
	[ IsGroup ],
	function ( G )
		local CCSG, cc, H, Q;
		if IsSolvableGroup( G ) then
			TryNextMethod();
		fi;
		if IsMonomial( G ) then
			return false;
		fi;
		CCSG := ConjugacyClassesSubgroups( G );
		for cc in CCSG do
			H := Representative( cc );
			if G = H or IsTrivial( H ) then
				continue;
			fi;
			if not IsMonomial( H ) then
				return false;
			fi;
			if Size( cc ) = 1 then
				Q := FactorGroupNC( G, H );
				if not IsMonomial( Q ) then
					return false;
				fi;
			fi;
		od;
		return true;
	end
);


gap> AllGroups( Size, [ 1..100 ], IsMinimalNonmonomial );
[ <pc group of size 24 with 4 generators>, Alt( [ 1 .. 5 ] ) ]

Best,
Sam
________________________________________
From: Bill Allombert <Bill.Allombert at math.u-bordeaux.fr>
Sent: 02 May 2021 00:21
To: GAP Forum
Subject: [GAP Forum] IsMinimalNonmonomial(AlternatingGroup(5));

Dear Forum,

I found

gap> IsMinimalNonmonomial(AlternatingGroup(5));
Error, no method found! For debugging hints type ?Recovery from
NoMethodFound
Error, no 3rd choice method found for `IsMinimalNonmonomial' on 1
arguments at /usr/share/gap/lib/methsel2.g:249 called from

Is it expected ?

I found this while doing:
gap> AllGroups(Size,[1..100],IsMinimalNonmonomial,true);
Error, no method found! For debugging hints type ?Recovery from

Cheers,
Bill.

_______________________________________________
Forum mailing list
Forum at gap-system.org
https://mail.gap-system.org/mailman/listinfo/forum