Re: Multiplying permutations
- To: mathgroup at smc.vnet.net
- Subject: [mg41765] Re: [mg41723] Multiplying permutations
- From: Bobby Treat <drmajorbob+MathGroup3528 at mailblocks.com>
- Date: Wed, 4 Jun 2003 08:34:46 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
If you'll use permutations much at all, I can recommend Hibbard and
Levasseur's book "Exploring Abstract Algebra with Mathematica", which
comes with a nice package that includes all sorts of useful stuff,
including MultiplyPermutations.
The capability may be hidden somewhere in Combinatorica, but the
operative word there is "hidden". I think you have to buy the
Combinatorica book, and it may be smarter to buy the Hibbard-Levasseur
book, depending on your needs.
The AbstractAlgebra package also includes simple, but often useful
things like unsorted set unions and complements, CartesianProduct,
SubsetQ, ShowPermutation, CayleyTable, etc.
Bobby
-----Original Message-----
From: Dr. Wolfgang Hintze <weh at snafu.de>
To: mathgroup at smc.vnet.net
Subject: [mg41765] [mg41723] Multiplying permutations
Is there a simple command in Mathematica to multiply two permutations,
i.e. to carry out one after the other?
I looked at the packages DiscreteMath`Permutations` and
DiscreteMath`Combinatorica` but couldn't find it.
Example
p = {3,1,2} mapping: 1->3, 2->1, 3->2
q = {2,1,3} mapping: 1->2, 2->1, 3->3
p.q = mappings (p first, then q)
[1-p->3-q->3, 2-p->1-q->2, 3-p->2-q->1]
= {3,2,1}
Any help appreciated
Wolfgang