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Le Monde puzzle [#1045]

March 19, 2018

An arithmetic Le Monde mathematical puzzle of limited proportions (also found on Stack Exchange): If x,y,z are distinct positive integers such that x+y+z=19 and xyz=p, what is the value of p that has several ordered antecedents?  If the sum is now x+y+z=22, is there a value of p=xyz for which there are several ordered antecedents? […]

Le Monde puzzle [#1044]

March 12, 2018

A dynamic programming Le Monde mathematical puzzle: Bob and Alice are playing a game where Alice fills a one-litre bottle from a water fountain, and empties it between four buckets. Bob then empties two of the four buckets. Alice then fills again her bottle and empties it again in the buckets. Alice wins if she […]

Le Monde puzzle [#1043]

March 5, 2018

An arithmetic Le Monde mathematical puzzle : A number is “noble” if all its digits are different and if it is equal to the average of all numbers created by permuting its digits. What are the noble numbers? There is no need for simulation when plain enumeration works. After failing to install the R packge […]

Le Monde puzzle [#1037]

January 24, 2018

A purely geometric Le Monde mathematical puzzle this (or two independent ones, rather): Find whether or not there are inscribed and circumscribed circles to a convex polygon with 2018 sides of lengths ranging 1,2,…,2018. In the first (or rather second) case, the circle of radius R that is tangential to the polygon and going through […]

machine learning à l’Académie, au Collège, et dans Le Monde

January 5, 2018

A back-cover story in Le Monde “Sciences & Médecine” of Stéphane Mallat, professor at École Normale and recently elected at the (French) Academy of Sciences and at the Collège de France, on a newly created Chair of Data Sciences.  With works on wavelets, image compression, and neural networks, Stéphane Mallat will give his first lesson […]