[GAP Forum] ClosureGroup!

[Bill Allombert]

On Sat, Oct 12, 2019 at 12:17:37PM +0000, lopo apelo kosho wrote:
> Dear friends, 
> I am writing a GAP code to check the following property: The join of any two permutable subgroup is a PERMUTABLE subgroup. I have a code that gives all permutable subgroups in a given group (PermutableSubgroups(g)). Here is my code:
> 
> 
> IsPermJoinGroup:=function(g)local i,n,j,c;
> 
> if IsAbelian(g)=truethen 
> 
> return true;
> 
> fi; 
> 
> n:=PermutableSubgroups(g);
> 
> if Size(n)=1 then return true;
> 
> fi;
> 
> for i in[1..Size(n)] do 
> 
> for j in [i+1..n]do
               ^^^
You should probably replace [i+1..n] by [i+1..Size(n)]

In fact you should probably rename n to N and set
N:=PermutableSubgroups(g);
n:=Size(N);
this would make your code more readable.

Cheers,
Bill