Dear GAP Forum,

Lewis McCarthy asked:

For a paper I'm writing I want to include a brief discussion of the origins
and history of GAP. Joachim Neubuser's June `94 preface to the GAP manual
has proven invaluable in this regard. However, I remain partly unclear about
the original motivations for creating GAP. Specifically, what aspects of
(for example) the CAYLEY system (now MAGMA) and the work of Pless/Leon et al.
at UIC made those systems undesirable in contrast to the GAP design ?

Since we have established the tradition to answer all questions posed
in the GAP forum, we have to answer this one, too, and I am afraid I
have to answer. I discussed possible answers with some members of our
team and a very short formulation proposed was: 'We did not like
Cayley, we did like Maple, and fortunately we did not realize what we
were going in for.' All three parts of that statement are true and the
last one even more than the first two, if e.g. I think of myself
writing this letter just now.

But seriously now:

Very clearly Cayley was a very strong and in many ways userfriendly
system already when we started GAP and had been used by many people
with great success. It was not, and Magma still is not, however, what
I call an 'open' system in the preface to the GAP manual. Various
aspects of what I mean by that are detailed in the last section 'Some
concerns' of my paper 'An Invitation to Computational Group Theory'
which is printed in Campbell et al., ed's., Groups '93,
Galway/St.Andrews, vol. 2, p. 457 - 475, (and which is also on my
web page). This paper rather closely follows a talk that I gave on
the first day of that conference as an introduction to a workshop on
CGT that we organised during the second week, and which I (ab?)used to
express some rather personal opinions.

I should mention perhaps that at an earlier time of the so-called
'Aachen Sydney Group System' which was a forerunner of Cayley as well
as of the first version of the system of Vera Pless, we had cooperated
very closely with John Cannon, and though of course the code from that
time has meanwhile been tranlated from Fortran to C and over and over
improved and rewritten by him, at least at the time of the first
release of Magma there were still some parts of code (in this
transformed state) in Magma, which originated from Aachen. However
even at the time of close cooperation when we had a copy of the source
of the group theoretical functions of the system we still had not
access to all, e.g. we were not able to experiment with modifications
of the language.

Thanks in advance for any comments on this topic. (Perhaps I should mention
that there are no current plans to publish this paper in a research journal.)

Glad to hear that, I hope that neither GAP nor even me have become
history yet.

P.S. Is the preface on the GAP manual web page somewhere ?

No.

Kind regards Joachim Neubueser