**A** short announcement that the slides of almost all talks at the CRiSM workshop on estimating constants last April 20-22 are now available. Enjoy (and dicuss)!

## Archive for partition

## CRiSM workshop on estimating constants [#2]

Posted in pictures, Statistics, Travel, University life, Wines with tags Bayesian computing, CRiSM, evidence, Monte Carlo Statistical Methods, normalising constant, partition, poster session, University of Warwick, workshop, Zeeman building on March 31, 2016 by xi'an**T**he schedule for the CRiSM workshop on estimating constants that Nial Friel, Helen Ogden and myself host next April 20-22 at the University of Warwick is now set as follows. (The plain registration fees are £40 and accommodation on the campus is available through the online form.)

**April 20, 2016**

11:45 — 12:30: Adam Johansen

*12:30 — 14:00: Lunch*

14:00 — 14:45: Anne-Marie Lyne

14:45 — 15:30: Pierre Jacob

*15:30 — 16:00: Break*

16:00 — 16:45: Roberto Trotta

17:00 — 18:00: ‘Elevator’ talks

18:00 — 20:00: Poster session, Cheese and wine

** April 21, 2016**

9:00 — 9:45: Michael Betancourt

9:45 — 10:30: Nicolas Chopin

*10:30 — 11:00: Coffee break*

11:00 — 11:45: Merrilee Hurn

11:45 — 12:30: Jean-Michel Marin

*12:30 — 14:00: Lunch*

14:00 — 14:45: Sumit Mukherjee

14:45 — 15:30: Yves Atchadé

*15:30 — 16:00: Break*

16:00 — 16:45: Michael Gutmann

16:45 — 17:30: Panayiota Touloupou

*19:00 — 22:00: Dinner*

**April 22, 2016**

9:00 — 9:45: Chris Sherlock

9:45 — 10:30: Christophe Andrieu

*10:30 — 11:00: Coffee break*

11:00 — 11:45: Antonietta Mira

## CRiSM workshop on estimating constants [#1]

Posted in pictures, Statistics, Travel, University life with tags Bayesian computing, CRiSM, evidence, Monte Carlo Statistical Methods, normalising constant, partition, poster session, University of Warwick, workshop, Zeeman building on January 19, 2016 by xi'an**T**he registration for the CRiSM workshop on estimating constants that Nial Friel, Helen Ogden and myself host next April 20-22 at the University of Warwick is now open. The plain registration fees are £40 and accommodation on the campus is available through the same form.

Since besides the invited talks, the workshop will host two poster session with speed (2-5mn) oral presentations, we encourage all interested researchers to submit a poster via the appropriate form. Once again, this should be an exciting two-day workshop, given the on-going activity in this area.

## on estimating constants…

Posted in pictures, Statistics, Travel, University life with tags Bayesian computing, CRiSM, evidence, Monte Carlo Statistical Methods, normalising constant, partition, poster session, University of Warwick, workshop, Zeeman building on July 21, 2015 by xi'an**W**hile I discussed on the ‘Og in the past the difference I saw between estimating an unknown parameter from a distribution and evaluating a normalising constant, evaluating such constants and hence handling [properly] doubly intractable models is obviously of the utmost importance! For this reason, Nial Friel, Helen Ogden and myself have put together a CRiSM workshop on the topic (with the tongue-in-cheek title of *Estimating constants*!), to be held at the University of Warwick next April 20-22.

The CRiSM workshop will focus on computational methods for approximating challenging normalising constants found in Monte Carlo, likelihood and Bayesian models. Such methods may be used in a wide range of problems: to compute intractable likelihoods, to find the evidence in Bayesian model selection, and to compute the partition function in Physics. The meeting will bring together different communities working on these related problems, some of which have developed original if little advertised solutions. It will also highlight the novel challenges associated with large data and highly complex models. Besides a dozen invited talks, the schedule will highlight two afternoon poster sessions with speed (2-5mn) oral presentations called ‘Elevator’ talks.

While 2016 is going to be quite busy with all kinds of meetings (MCMSkv, ISBA 2016, the CIRM Statistics month, AISTATS 2016, …), this should be an exciting two-day workshop, given the on-going activity in this area, and I thus suggest interested readers to mark the dates in their diary. I will obviously keep you posted about registration and accommodation when those entries are available.

## Le Monde puzzle [#822]

Posted in Books, Kids, R with tags combinatorics, induction, Le Monde, mathematical puzzle, odd numbers, partition, R on June 10, 2013 by xi'an**F**or once Le Monde math puzzle is much more easily solved on a piece of paper than in R, even in a plane from Roma:

Given a partition of the set {1,…,N} in k groups, one considers the collection of all subsets ofthe set {1,…,N} containing at least one element from each group. Show that the size of the collection cannot be 50.

**O**bviously, one could consider a range of possible N’s and k’s and run a program evaluating the sizes of the corresponding collections. However, if the k groups are of size n_{1},…,n_{k}, the number of subsets satisfying the condition is

and it is easily shown by induction that this number is necessarily odd, hence the impossible 50.