On Mon, Sep 05, 2011 at 11:59:02PM -0700, Anne Schilling wrote:
> I now implemented another version of this method which is recursive
> (the two methods are bruhat_upper_cover and bruhat_upper_cover_old).
> I am not sure the complexity is any better though.
I like it, and am pretty sure it is much better. Can you make a quick
benchmark? Say by computing all bruhat upper covers for S4 / S5 / S6
using the old and new algorithm, as well as using the method for
finite coxeter groups?
> That is ensured by the conditions on the descents of the left and right
> factor.
That's what I was pondering: those conditions sure guarantee that
there is no immediate cancellation with the left or right factor; it's
not immediately obvious to me that it does guarantee that there is no
more complicated cancellation involving the left and right factors and
the s_i in the middle.
> Ok, I deleted this for the old method, but kept it for the new
> method since it is recursive.
+1!
Cheers,
Nicolas
--
Nicolas M. Thiéry "Isil" <nthi...@users.sf.net>
http://Nicolas.Thiery.name/
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