> < ^ From:

> < ^ Subject:

Dear Forum,

Mario Pineda asked:

I am interesed on calculating the stabilizer of a point and I would be

greateful if some could help with the instructions that I need to tell

GAP(3.4 For PowerBook Mac) to do it.

To be more specific, I need to know to specify the command "opr".

<opr> is a function which defines the operation. Its syntax is

opr(<point>,<groupel>) and it should compute the image of the point under

the group element.

For standard operations there are some operations predefined: OnPoints (the

operation via ^, for example of a permutation group on points) and OnRight

(right multiplication, as a matrix group acts on a vector space).

If these specific operations are given, GAP may be able to use a better

algorithm in specific cases.

If you don't give an operation, 'OnPoints' is assumed.

So, for example:

g:=Group((1,2,3,4),(1,2));

s:=Stabilizer(g,4); returns the same as Stabilizer(g,4,OnPoints);

namely the group S3 as subgroup of S4.

Best regards,

Alexander Hulpke

> < [top]