Hi Rob!
(CC to sage-combinat; this is thread [1] on sage-devel)
On Tue, Sep 04, 2012 at 07:36:51AM -0700, Rob Beezer wrote:
> On Tuesday, September 4, 2012 6:21:11 AM UTC-7, John Cremona wrote:
>
> If pi is a permutation, e.g. defined by pi=permutations(4)[3], then
> pi.signature() returns what I have always called the "sign" of pi, and
> none of pi.sign(), pi.sgn(), sign(pi), sgn(pi) work.
>
> But:
>
> sage: G = SymmetricGroup(2)
> sage: a = G("(1,2)")
> sage: a.sign()
> -1
>
> So I'd say +1 to greater coordination between group element permutations
> and purely combinatorial permutations overall, and in particular having
> .sign() as John suggests for the "other" permutations.
+1! This miscoordination has been an itch for us for quite a while.
In general, Permutations need some heavy refactoring which will be
best done all at once; but a simple change like this can be done right
away.
Cheers,
Nicolas
PS:
https://groups.google.com/forum/?hl=fr&fromgroups=#!topic/sage-devel/DYVbTWWOMtE)
--
Nicolas M. Thiéry "Isil" <nthi...@users.sf.net>
http://Nicolas.Thiery.name/
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