[GAP Forum] Migrating from GAP 3 to GAP 4

[Alexander Hulpke]

Dear Forum,

On Jun 22, 2014, at 6:22 AM, Hebert Pérez-Rosés <hebert.perez at gmail.com> wrote:

> Dear all,
> 
> I have some old programs written in GAP 3, which I would like to translate
> into GAP 4. The programs work with finitely presented groups, or rather,
> with words on some abstract generators. For example, I have a program that
> encodes a presentation of the alternating group A_5:
> 
> a:=AbstractGenerator("a");
> b:=AbstractGenerator("b");
> c:=AbstractGenerator("c");
> 
> Gens:=[a,b,c];

In GAP4 you would first create a free group:

F:=FreeGroup("a","b","c");
and then get the generators as
a:=F.1;b:=F.2;c:=F.3;
or (quicker) call
AssignGeneratorVariables(F);
if you set
IdWord:= One(F);

your existing `Rels' assignment will work.

Regards,

   Alexander Hulpke

-- Colorado State University, Department of Mathematics,
Weber Building, 1874 Campus Delivery, Fort Collins, CO 80523-1874, USA
email: hulpke at math.colostate.edu, Phone: ++1-970-4914288
http://www.math.colostate.edu/~hulpke