[Excerpts from an editorial in the NYT of John Irving, American author of the Cider House Rules novel we enjoyed reading 30 years ago] “(…) I respect your personal reasons not to have an abortion — no one is forcing you to have one. I respect your choice. I’m pro-choice — often called pro-abortion by […]

# Author: xi'an

## natural LaTeX

Nature must have been out of inspiration in the past weeks for running a two-page article on LaTeX [as the toolbox column] and how it compares with… Word! Which is not so obvious since most articles in Nature are not involving equations (much) and are from fields where Word prevails. Besides the long-running whine that […]

## a non-riddle

Unless I missed a point in the last riddle from the Riddler, there is very little to say about it: Given N ocre balls, N aquamarine balls, and two urns, what is the optimal way to allocate the balls to the urns towards drawing an ocre ball with no urn being empty? Both my reasoning […]

## the most probable cluster

In the last issue of Bayesian Analysis, Lukasz Rajkowski studies the most likely (MAP) cluster associated with the Dirichlet process mixture model. Reminding me that most Bayesian estimates of the number of clusters are not consistent (when the sample size grows to infinity). I am always puzzled by this problem, as estimating the number of […]

## CRAN does not validate R packages!

A friend called me the other day for advice on how to submit an R package to CRAN along with a proof his method was mathematically sound. I replied with some items of advice taken from my (limited) experience with submitting packages. And with the remark that CRAN would not validate the mathematical contents of […]

## and it only gets worse [verbatim]

“Increasing export capacity from the Freeport LNG project is critical to spreading freedom gas throughout the world by giving America’s allies a diverse and affordable source of clean energy” M. Menezes, US Secretary of Energy “NASA should NOT be talking about going to the Moon – We did that 50 years ago. They should be […]

## Le Monde puzzle [#1107]

A light birthday problem as Le Monde mathematical puzzle: Each member of a group of 35 persons writes down the number of those who share the same birth-month and the number of those who share the same birth-date [with them]. It happens that these 70 numbers include all integers from 0 to 10. Show that […]

## Le Monde puzzle [#1105]

Another token game as Le Monde mathematical puzzle: Archibald and Beatrix play with a pile of n>100 tokens, sequentially picking m tokens from the pile with m being a prime number [including m=1] or a multiple of 6, the winner taking the last tokens. If Beatrix knows n and proposes to Archibald to start, what […]

## good omens and bad jokes

Following the news that members of a religious sect had petitioned Netflix not to show Good Omens as they deemed the story blasphemous, mistaking Netflix for Amazon Prime!, I could not resist but engage into watching this show. While having skipped reading the original book. as I am fairly tone-deaf when it comes to Terry […]

## art brut

## Le Monde puzzle [#1106]

A linear equation as Le Monde mathematical puzzle:

Find the ten integers x¹,x²,…. such that Ax=3x-1 where

Which returns 38 44 31 38 44 49 16 16 31 27 as its solution and is definitely of limited appeal…

## a generalized representation of Bayesian inference.

Jeremias Knoblauch, Jack Jewson and Theodoros Damoulas, all affiliated with Warwick (hence a potentially biased reading!), arXived a paper on loss-based Bayesian inference that Jack discussed with me on my last visit to Warwick. As I was somewhat scared by the 61 pages, of which the 8 first pages are in NeurIPS style. The authors […]

## O’Bayes 19/4

Last talks of the conference! With Rui Paulo (along with Gonzalo Garcia-Donato) considering the special case of factors when doing variable selection. Which is an interesting question that I had never considered, as at best I would remove all leves or keeping them all. Except that there may be misspecification in the factors as for […]

## O’Bayes 19/3.5

Among the posters at the second poster session yesterday night, one by Judith ter Schure visually standing out by following the #betterposter design suggested by Mike Morrison a few months ago. Design on which I have ambivalent feelings. On the one hand, reducing the material on a poster is generally a good idea as […]

## O’Bayes 19/3

Nancy Reid gave the first talk of the [Canada] day, in an impressive comparison of all approaches in statistics that involve a distribution of sorts on the parameter, connected with the presentation she gave at BFF4 in Harvard two years ago, including safe Bayes options this time. This was related to several (most?) of the […]

## O’Bayes 19/2

One talk on Day 2 of O’Bayes 2019 was by Ryan Martin on data dependent priors (or “priors”). Which I have already discussed in this blog. Including the notion of a Gibbs posterior about quantities that “are not always defined through a model” [which is debatable if one sees it like part of a semi-parametric […]

## O’Bayes 19/1 [snapshots]

Although the tutorials of O’Bayes 2019 of yesterday were poorly attended, albeit them being great entries into objective Bayesian model choice, recent advances in MCMC methodology, and the multiple layers of BART, for which I have to blame myself for sticking the beginning of O’Bayes too closely to the end of BNP as only the […]

## O’Bayes 19/1 [snapshots]

Although the tutorials of O’Bayes 2019 of yesterday were poorly attended, albeit them being great entries into objective Bayesian model choice, recent advances in MCMC methodology, and the multiple layers of BART, for which I have to blame myself for sticking the beginning of O’Bayes too closely to the end of BNP as only the […]

## running after my plane

A bit of a hectic trip to Abidjan last Sunday, starting from Caen in the early morning where I was supporting my daughter, wife, mother, and mother-in-law for the annual Rochambelle women-only 5k race on the previous evening! With my daughter managing a fantastic 52nd position and ending up first of her category! As I […]

## O’Bayes 2019 has now started!

The O’Bayes 2019 conference in Warwick University has now started, with about 100 participants meeting over four days (plus one of tutorials) in the Zeeman maths building of the University. Quite a change of location and weather when compared with the previous one in Austin. As an organiser I hope all goes well at the […]