Blog Archives

Egyptian fractions [Le Monde puzzle #922]

July 27, 2015
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Egyptian fractions [Le Monde puzzle #922]

For its summer edition, Le Monde mathematical puzzle switched to a lighter version with immediate solution. This #922 considers Egyptian fractions which only have distinct denominators (meaning the numerator is always 1) and can be summed. This means 3/4 is represented as ½+¼. Each denominator only appears once. As I discovered when looking on line, […]

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Le Monde puzzle [#920]

July 22, 2015
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Le Monde puzzle [#920]

A puzzling Le Monde mathematical puzzle (or blame the heat wave): A pocket calculator with ten keys (0,1,…,9) starts with a random digit n between 0 and 9. A number on the screen can then be modified into another number by two rules: 1. pressing k changes the k-th digit v whenever it exists into […]

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MCMskv, Lenzerheide, 4-7 Jan., 2016 [news #1]

July 19, 2015
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MCMskv, Lenzerheide, 4-7 Jan., 2016 [news #1]

The BayesComp MCMski V [or MCMskv for short] has now its official website, once again maintained by Merrill Lietchy from Drexel University, Philadelphia, and registration is even open! The call for contributed sessions is now over, while the call for posters remains open until the very end. The novelty from the previous post is that there […]

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Leave the Pima Indians alone!

July 14, 2015
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Leave the Pima Indians alone!

“…our findings shall lead to us be critical of certain current practices. Specifically, most papers seem content with comparing some new algorithm with Gibbs sampling, on a few small datasets, such as the well-known Pima Indians diabetes dataset (8 covariates). But we shall see that, for such datasets, approaches that are even more basic than […]

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R brut

July 2, 2015
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R brut

Filed under: Kids, pictures, R, Statistics, University life Tagged: cex, pch, plot, R

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Introduction to Monte Carlo methods with R and Bayesian Essentials with R

June 26, 2015
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Introduction to Monte Carlo methods with R and Bayesian Essentials with R

Here are the  download figures for my e-book with George as sent to me last week by my publisher Springer-Verlag.  With an interesting surge in the past year. Maybe simply due to new selling strategies of the published rather to a wider interest in the book. (My royalties have certainly not increased!) Anyway thanks to […]

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arXiv frenzy

June 23, 2015
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arXiv frenzy

In the few past days, there has been so many arXiv postings of interest—presumably the NIPS submission effect!—that I cannot hope to cover them in the coming weeks! Hopefully, some will still come out on the ‘Og in a near future: arXiv:1506.06629: Scalable Approximations of Marginal Posteriors in Variable Selection by Willem van den Boom, […]

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dynamic mixtures [at NBBC15]

June 17, 2015
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dynamic mixtures [at NBBC15]

A funny coincidence: as I was sitting next to Arnoldo Frigessi at the NBBC15 conference, I came upon a new question on Cross Validated about a dynamic mixture model he had developed in 2002 with Olga Haug and Håvård Rue [whom I also saw last week in Valencià]. The dynamic mixture model they proposed replaces […]

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the Flatland paradox [#2]

May 26, 2015
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the Flatland paradox [#2]

Another trip in the métro today (to work with Pierre Jacob and Lawrence Murray in a Paris Anticafé!, as the University was closed) led me to infer—warning!, this is not the exact distribution!—the distribution of x, namely since a path x of length l(x) will corresponds to N draws if N-l(x) is an even integer […]

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another viral math puzzle

May 24, 2015
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another viral math puzzle

After the Singapore Maths Olympiad birthday problem that went viral, here is a Vietnamese primary school puzzle that made the frontline in The Guardian. The question is: Fill the empty slots with all integers from 1 to 9 for the equality to hold. In other words, find a,b,c,d,e,f,g,h,i such that a+13xb:c+d+12xe–f-11+gxh:i-10=66. With presumably the operation […]

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