# [GAP Forum] ? trouble getting started ?

Brian Beckman brianbec at comcast.net
Sun Jul 25 18:44:07 BST 2004

```Hello --

I had some trouble understanding Permutations as presented in the tutorial
and I wondered whether someone might help me out.

I'm working through
http://www.gap-system.org/Manuals/doc/htm/tut/CHAP002.htm#SECT008 .  I was
able to understand "conjugating" permutations with the "caret" operator, so,
for instance, (1,2)^(1,2,3)=(2,3); made sense to me and
(1,2,3)^(1,2)=(1,3,2); also made sense.  I could not figure out
"multiplication" of purmutations, however, so (1,2)*(1,2,3)=(1,3); did not
make sense to me and (1,2,3)*(1,2)=(2,3); did not make sense. I expected
(1,2)*(1,2,3)=(1,2,3)^(1,2) and (1,2,3)*(1,2)=(1,2)^(1,2,3), but that's
obviously not the case.

I apologize for my ignorance of the subject, but I am attempting to use GAP
to learn algebra.  So far, I only know of one kind of operation for
permutations (that being composition or conjugation) and I couldn't quickly
figure out what your multiplication means. I'll continue to play around with
it and may possibly find my own answer, but it's humiliating to get
frustrated by the very first algebraic operation I attempted here.

Regards,
Brian Beckman

```