# [GAP Forum] RE: Forum Digest, Vol 6, Issue 4 (fwd)

Joachim Neubueser joachim.neubueser at math.rwth-aachen.de
Wed Jun 2 14:49:17 BST 2004

```Dear Rashid Ali,

You wrote to the GAP Forum:

> Dear Forum Members

> I  am  working on  computations  of  Self-Connected and  H-Connected
> transversals of a group G.  Since total number of transversals for a
> finite  group  G  with  a  subgroup H  =  Order(H)^Index(G,H).  I've
> designed an  algorithm that searches  self-connected and H-connected
> transversals.  It works  properly  for small  groups  but for  large
> gooups  say  for example  when  Order(G)=1792,  and Order(H)=64,  it
> perform  computations  for  many  hours  but it  quits  gap  session
> automatically  leaving  the  executation  incomplete,  and  displays
> following message that I'm unable to understand:

> 0     [main]    gapw95     1116     handle_exceptions:    Exception:
> STATUS_ACCESS_VIOLATION
>
> 1062  [main]   gapw95  1116   stackdump:  Dumping  stack   trace  to
> gapw95.exe.stackdump

> I can't understand how to resolve this problem
>
> Regards
>
> Rashid Ali

I have  seen that  you got some  reply dealing with  problems possibly
stemming from using Windows rather than Unix.

However  for me  the main  problem  is that  I do  not understand  the
mathematical  problem  that you  are  dealing  with.   What are  'Self
Connected' and  'H-Connected' transversals of  a subgroup of  a finite
group? These terms  are not standard, I have  never heard them.  Could
you  provide definitions  of these  terms, give  references  to papers
where they  are used, and  could you tell  for which groups  and which
subgroups you want to do the  computation? Only then there is a chance
that we may be able to really give you some advice.

With kind regards     Joachim Neubueser

----------------------------------------------------------------------
Prof. em. J. Neubueser
Lehrstuhl D fuer Mathematik
RWTH Aachen
Germany

```