Archive for Université de Montpellier

postdoc position still open

Posted in pictures, Statistics, University life with tags , , , , , , , , , , , , , , on May 30, 2019 by xi'an

The post-doctoral position supported by the ANR funding of our Paris-Saclay-Montpellier research conglomerate on approximate Bayesian inference and computation remains open for the time being. We are more particularly looking for candidates with a strong background in mathematical statistics, esp. Bayesian non-parametrics, towards the analysis of the limiting behaviour of approximate Bayesian inference. Candidates should email me (gmail address: bayesianstatistics) with a detailed vita (CV) and a motivation letter including a research plan. Letters of recommendation may also be emailed to the same address.

Garrigue administrative

Posted in Books, pictures, University life with tags , , , , on May 20, 2019 by xi'an

A central page in Le Monde of this week (May 08), about the conundrum of dealing with the dozens of thousands of handwritten pages left by Alexandre Grothendiek, from trying to make sense of the contents to assessing the monetary value (!) of such documents. Mentioning that the most reasonable solution would be to extend the numerisation of earlier documents supervised by Jean-Michel Marin. Given the difficulty in reading these pages, as suggested by Le Monde, training an AI to translate them into regular text would make sense, if not helping with evaluating their importance…

absint[he] post-doc on approximate Bayesian inference in Paris, Montpellier and Oxford

Posted in Statistics with tags , , , , , , , , , , , , , on March 18, 2019 by xi'an

As a consequence of its funding by the Agence Nationale de la Recherche (ANR) in 2018, the ABSint research conglomerate is now actively recruiting a post-doctoral collaborator for up to 24 months. The accronym ABSint stands for Approximate Bayesian solutions for inference on large datasets and complex models. The ABSint conglomerate involves researchers located in Paris, Saclay, Montpelliers, as well as Lyon, Marseille, Nice. This call seeks candidates with an excellent research record and who are interested to collaborate with local researchers on approximate Bayesian techniques like ABC, variational Bayes, PAC-Bayes, Bayesian non-parametrics, scalable MCMC, and related topics. A potential direction of research would be the derivation of new Bayesian tools for model checking in such complex environments. The post-doctoral collaborator will be primarily located in Université Paris-Dauphine, with supported periods in Oxford and visits to Montpellier. No teaching duty is attached to this research position.

Applications can be submitted in either English or French. Sufficient working fluency in English is required. While mastering some French does help with daily life in France (!), it is not a prerequisite. The candidate must hold a PhD degree by the date of application (not the date of employment). Position opens on July 01, with possible accommodation for a later start in September or October.

Deadline for application is April 30 or until position filled. Estimated gross salary is around 2500 EUR, depending on experience (years) since PhD. Candidates should contact Christian Robert (gmail address: bayesianstatistics) with a detailed vita (CV) and a motivation letter including a research plan. Letters of recommendation may also be emailed to the same address.

Le Monde puzzle [#1083]

Posted in Books, Kids, R, Travel with tags , , , , , , on February 7, 2019 by xi'an

A Le Monde mathematical puzzle that seems hard to solve without the backup of a computer (and just simple enough to code on a flight to Montpellier):

Given the number N=2,019, find a decomposition of N as a sum of non-trivial powers of integers such that (a) the number of integers in the sum is maximal or (b) all powers are equal to 4.  Is it possible to write N as a sum of two powers?

It is straightforward to identify all possible terms in these sums by listing all powers of integers less than N

pool=(1:trunc(sqrt(2019)))^2
for (pow in 3:11)
  pool=unique(c(pool,(2:trunc(2019^(1/pow)))^pow))

which leads to 57 distinct powers. Sampling at random from this collection at random produces a sum of 21 perfect powers:

 1+4+8+9+16+25+27+32+36+49+64+81+100+121+125+128+144+169+196+243+441

But looking at the 22 smallest numbers in the pool of powers leads to 2019, which is a sure answer. Restricting the terms to powers of 4 leads to the sequence

1⁴+2⁴+3⁴+5⁴+6⁴ = 2019

And starting from the pools of all possible powers in a decomposition of 2019 as the sum of two powers shows this is impossible.

MASH in Le Monde

Posted in Statistics with tags , , , , , , , , on January 25, 2019 by xi'an

exciting week[s]

Posted in Mountains, pictures, Running, Statistics with tags , , , , , , , , , , , , , , on June 27, 2017 by xi'an

The past week was quite exciting, despite the heat wave that hit Paris and kept me from sleeping and running! First, I made a two-day visit to Jean-Michel Marin in Montpellier, where we discussed the potential Peer Community In Computational Statistics (PCI Comput Stats) with the people behind PCI Evol Biol at INRA, Hopefully taking shape in the coming months! And went one evening through a few vineyards in Saint Christol with Jean-Michel and Arnaud. Including a long chat with the owner of Domaine Coste Moynier. [Whose domain includes the above parcel with views of Pic Saint-Loup.] And last but not least! some work planning about approximate MCMC.

On top of this, we submitted our paper on ABC with Wasserstein distances [to be arXived in an extended version in the coming weeks], our revised paper on ABC consistency thanks to highly constructive and comments from the editorial board, which induced a much improved version in my opinion, and we received a very positive return from JCGS for our paper on weak priors for mixtures! Next week should be exciting as well, with BNP 11 taking place in downtown Paris, at École Normale!!!

Grothendieck’s papers on-line!

Posted in Books, Kids, University life with tags , , , on May 10, 2017 by xi'an

Today, the University of Montpellier will put on-line the series of 18,000 pages of manuscripts of Alexandre Groethendieck that it had digitised a few years ago. Thanks to the efforts of Jean-Michel Marin, the nearly incomprehensible legal imbroglio on the rights of both the University and the children of Groethendieck has been unravelled, meaning that the University is now allowed to make the manuscripts available, while the children have the sole property of the dozens of thousands of pages written by Groethendieck till his death. It is hard to imagine how such a volume can be efficiently explored and exploited to uncover new mathematical advances made by Groethendieck in the last and secluded part of his life, but at last the raw material is available for all to try.