Category: Kids

Le Monde puzzle [#1104]

A palindromic Le Monde mathematical puzzle: In a monetary system where all palindromic amounts between 1 and 10⁸ have a coin, find the numbers less than 10³ that cannot be paid with less than three coins. Find if 20,191,104 can be paid with two coins. Similarly, find if 11,042,019 can be paid with two or […]

another attempt at code golf

I had another lazy weekend go at code golf, trying to code in the most condensed way the following task. Provided with a square matrix A of positive integers, keep iterating the steps take the highest square 𝑥² in A. find the smallest adjacent neighbour 𝑛 replace x² with x and n with nx until […]

riddles on Egyptian fractions and Bernoulli factories

Two fairy different riddles on the weekend Riddler. The first one is (in fine) about Egyptian fractions: I understand the first one as Find the Egyptian fraction decomposition of 2 into 11 distinct unit fractions that maximises the smallest fraction. And which I cannot solve despite perusing this amazing webpage on Egyptian fractions and making […]

the Kouign-Amann experiment

Having found a recipe for Kouign-Amanns, these excessive cookies from Britanny that are essentially cooked salted butter!, I had a first try that ended up in disaster (including a deep cut on the remaining thumb) and a second try that went better as both food and body parts are concerned. (The name means cake of […]

Lawrence D. Brown PhD Student Award

[Reproduced from the IMS Bulletin, an announcement of a travel award for PhD students in celebration of my friend Larry Brown!] Lawrence D. Brown (1940-2018), Miers Busch Professor and Professor of Statistics at The Wharton School, University of Pennsylvania, had a distinguished academic career with groundbreaking contributions to a range of fields in theoretical and […]

logicomix redux

I had not made the link until the last speaker of the 50 years of Dauphine commemoration was introduced that he was one of the authors of Logicomix. He spoke of the mathematical modeling of neurons and brain activity, rather than comics, but at a very low level that he called cartoonesque. It is a […]

end of the game

While I have not watched a large part of the Game of Thrones episodes (apart from the first season I had time to follow while in the hospital), I decided to subscribe for one [free] month to OCS to get the last and final season [unlike a NYT critic who watches the entire eight seasons […]

truncated Normal moments

An interesting if presumably hopeless question spotted on X validated: a lower-truncated Normal distribution is parameterised by its location, scale, and truncation values, μ, σ, and α. There exist formulas to derive the mean and variance of the resulting distribution,  that is, when α=0, and but there is no easy way to choose (μ, σ) […]

an attempt at code golf

Having discovered codegolf on Stack Exchange a few weeks ago, I spotted a few interesting puzzles since then but only got the opportunity at a try over a quiet and rainy weekend (and Robin being on vacation)! The challenge was to write an R code for deciding whether or not a given integer n is […]

O’Bayes 2019 conference program

The full and definitive program of the O’Bayes 2019 conference in Warwick is now on line. Including discussants for all papers. And the three [and free] tutorials on Friday afternoon, 28 June, on model selection (M. Barbieri), MCMC recent advances (G.O. Roberts) and BART (E.I. George). Registration remains open at the reduced rate and submissions […]

easy Riddler

The riddle of the week is rather standard probability calculus If N points are generated at random places on the perimeter of a circle, what is the probability that you can pick a diameter such that all of those points are on only one side of the newly halved circle? Since it is equivalent to […]

and it only gets worse…

. ” The Texas state legislature is debating a provision that wouldn’t just outlaw abortion, but legally qualify it as homicide(…) This, incidentally, is exactly what pro-choice advocates warned about when they said that a law passed in the George W Bush era, the Unborn Victims of Violence Act, as well as the related state […]

PhD studenships at Warwick

There is an exciting opening for several PhD positions at Warwick, in the departments of Statistics and of Mathematics, as part of the Centre for Doctoral Training in Mathematics and Statistics newly created by the University. CDT studentships are funded for four years and funding is open to students from the European Union without restrictions. […]

visualising bias and unbiasedness

A question on X validated led me to wonder at the point made by Christopher Bishop in his Pattern Recognition and Machine Learning book about the MLE of the Normal variance being biased. As it is illustrated by the above graph that opposes the true and green distribution of the data (made of two points) […]

Le Monde puzzle [#1099]

A simple 2×2 Le Monde mathematical puzzle: Arielle and Brandwein play a game out of two distinct even integers between 1500 and 2500,  and y. Providing one another with either the pair (x/2,y+x/2) or the pair (x+y/2,y/2) until they run out of even possibilities or exceed 6 rounds. When x=2304, what is the value of […]