Nov 28, 2014 @ Urania

Correspondence with Friday speaker

Dear Mimi,

I sent this title and abstract to the BMS people. For the pre-seminar, given or organized by you,
I suggest cell complexes modeling the complement of hyperplane arrangements. For real 
arrangements this leads to oriented matroids, for complex arrangements  the cell
complexes I have in mind are those considered in my paper with Günter ~1992
on combinatorial stratifications of complex arrangements.

What do you think of this suggestion? Would it be OK?



Title: Random walks on complex hyperplane arrangements and self-organising libraries

Abstract: The starting point is the pleasant fact that some much-studied random walks on permutations, such as the Tsetlin library, arise from walks on real hyperplane arrangements [Bidigare, Hanlon and Rockmore, 1998]. We explore similar walks on complex hyperplane arrangements. This is achieved by involving certain cell complexes that model the topology of the complement of the arrangement. In a particular case this leads to walks on dynamic Tsetlin-style libraries with several shelves. 

These random walks belong to a family of Markov chains, best described in terms of semigroups, that have been studied by K. Brown, P. Diaconis, and others. They have the property that all eigenvalues of the transition matrices are non-negative real and given by a simple combinatorial formula. Background material needed for understanding the walks and the geometric constructions will be reviewed in rather great detail. 


Correspondence with "What is ...?" speaker

It's a good bet. Let's do this. Either I do it myself or I find somebody else to do it.


On 11/17/2014 04:29 PM, Mimi Tsuruga wrote:
In case you are not able, is there someone else you know who might be able to do it?? I figure that our best bet is the Villa people...

- Mimi

On Mon, Nov 17, 2014 at 4:25 PM, Arnau Padrol <> wrote:
Hi Mimi,

in principle I'll be here (and if so I'll be willing to do it). However, I am quite busy and travelling a lot, and it's not 100% sure yet that I am going to be here that friday. Let me give you a final answer in a couple of days. (If I haven't told you anything by thursday, send me an angry email reminding me to do it.)



On 11/17/2014 04:11 PM, Mimi Tsuruga wrote:
Hi Arnau,

We need you again!!!

Bjoerner is scheduled to give a BMS Friday on Nov 28. He sent us the email below.

Perhaps you've already heard from Guenter that I was hoping to ask you to give the "What is ...?" talk preceding the Friday talk.

Are you available?? (and willing??)

Please let me know soon~~~~

Thank you!!!!!!!!!!!!!!

- Mimi


Topic revision: r2 - 18 Nov 2014, LutzPrechelt
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