[GAP Forum] semidirect products

[vbovdi at math.unideb.hu]

Dear Alexander  and Bettina,

Thank you very much.


Best regards, Victor Bovdi




> Dear GAP-forum, Dear Victor Bovdi,
>
>> Let A and B be finite 2-groups.
>> I am interested in the isomorphism classes of the semidirect (or/and
>> central) products of these groups.
>>
>> Do you know about a package which can aid this sort of calculation ?
>
> There is no function that does these calculations directly -- you would
> have to go step-by-step in determining
>
> - Calculate Aut(N)   (the package autpgrp will help)
> - Classify all homomorphisms from G to Aut(N)   (there will be a function
> `AllHomomorphismClasses' in GAP4 and i can send you code for this
> privately if you are interested).
> - Form the semidirect products using `SemidirectProduct'
> - Test for isomorphism (the `anupq' package can help here, as the
> extensions are p-groups)
>
> Best wishes,
>
>    Alexander Hulpke (with help from Bettina Eick)
>
> -- 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
>
>
>
>