[GAP Forum] Group from octonion elements

[Stephen Linton]

> On 11 Jan 2019, at 12:17, Marek Mitros <marek at mitros.org> wrote:
> 
> Hi,
> 
> I have defined octonions over field
> o:=OctaveAlgebra(GF(7));
> 
> Next create set of some invertible elements belonging to some subalgebra.
> And I wanted to see what group is generated by invertible elements in this
> subalgebra. Unfortunately I cannot use "Group" function, because I obtain
> error "no groups of cyclotomics allowed because of incomatible ^". I am
> using GAP version 4.8.8. This subalgebra is associative, because it is
> generated by two elements. Therefore invertible elements should form a
> group. Do you have any advice or workaround how could I test my group ? I
> wanted to use StructureDescription. These are small groups of size
> 294,336,392 and 686.
> 
> gap> g1:=Group([1..5],k->Random(c1i));

I think your problem is in this line. Group doesn’t work like that. Try
Group(List([1..5]….))

	Steve

> #I  no groups of cyclotomics allowed because of incompatible ^
> Error, usage: Group(<gen>,...), Group(<gens>), Group(<gens>,<id>) called
> from
> <function "Group">( <arguments> )
> called from read-eval loop at line 74 of *stdin*
> you can 'quit;' to quit to outer loop, or
> you can 'return;' to continue
> brk> quit;
> 
> Regards,
> Marek
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