Author Archive

“So President Emmanuel Macron of France called me on Thursday afternoon” [really?!]

Posted in Books with tags , , , , , , , , , on November 26, 2020 by xi'an

When I read this first sentence in The New York Times article by Ben Smith, I was a wee bit suprised as it sounded more Trumpian than Macronesque. Esp. when the article continued with the French president “having some bones to pick with the Anglo-American media”… As it transpired, it is factually correct, if giving an impression of the exact opposite of the right causality arrow. The Élysée palace indeed called back the NYT journalist after the latter asked for an interview a few days earlier and that Macron agreed to it. Beyond this misleading launch, the article is much more of an opinion piece (about Ben Smith’s opinions on French politics and secular principles) than an interview. Just like most principles, the rather specific core concept of “laïcité” (secularism) can be both debated ad nauseam and turned into political weapons for all positions on the political spectrum, from extreme-left to extreme-right. It is also almost invariably presented from abroad as an attack on the freedom of religion (and lack thereof), mostly against Muslims, and almost automatically mixed with institutional racism. The article actually goes all over the place, from attributing the uncovering of a pedophile writer to The Times journalists, to seeing Macron’s position as a theatrical posturing helping his own agenda for the next presidential elections. And while I readily concede the many woes of the French society, government, institutions, like police and justice, politics, &tc., I cannot but support an idea of a model that remains universalist and therefore secularist.

the riddle(r) of the certain winner losing in the end

Posted in Books, Kids, R, Statistics with tags , , , , , on November 25, 2020 by xi'an

Considering a binary random walk, starting at zero, what is the probability of being almost sure of winning at some point only to lose at the end? This is the question set by the post-election Riddler, with almost sure meaning above 99% and the time horizon set to n=101 steps (it could have been 50 or 538!). As I could not see a simple way to compute the collection of states with a probability of being positive at the end of at least 0.99, even after checking William Feller’s Random Walks fabulous chapter, I wrote an R code to find them, and then ran a Monte Carlo evaluation of the probability to reach this collection and still end up with a negative value. Which came as 0.00212 over repeated simulations. Obviously smaller than 0.01, but no considerably so. As seen on the above picture, the set to be visited is actually not inconsiderable. The bounding curves are the diagonal and the 2.33 √(n-t) bound derived from the limiting Brownian approximation to the random walk, which fits rather well. (I wonder if there is a closed form expression for the probability of the Brownian hitting the boundary 2.33 √(n-t). Simulations with 1001 steps give an estimated probability of 0.505, leading to a final probability of 0.00505 of getting over the boundary and loosing in the end, close to the 1/198 produced by The Riddler.)

CIRM in dire need of help

Posted in Mountains, pictures, Running, Statistics, Travel, University life, Wines with tags , , , , , , , , , , , , , , , on November 24, 2020 by xi'an

The International Mathematics Conference Centre, CIRM, located in Luminy, Marseille, France, has been deeply disrupted by the COVID-19 pandemic. Up to 60 % of the events planned there have been cancelled so far and all remaining conferences have gone virtual or at best hybrid, open to a remote audience, including in an interactive way. This has required important and unexpected investments. Furthermore, this crisis happened at the worst possible moment as CIRM had just finished doubling its infrastructure capacities. This is why I strongly support the call from the French Mathematical Society (SMF) to make a donation to CIRM before the end of the year, especially from researchers who benefited from its hospitality and unique environment.

false value

Posted in Statistics with tags , , , , , , , , , , , on November 23, 2020 by xi'an

A very pleasant eighth volume in the Rivers of London series after a few so-so episodes! The relentless deadpan of Peter Grant is back full shape, the plot is substantial and gripping, new and well-drawn characters abound, and the story offers an original retelling of the Difference Engine. (Not that I have reservations about Gibbson’s plus Sterling’s 1990 version!) Including mentions of Jacquard’s loom, card fed organ automates, Ada Lovelace and Mary Somerville. Plus providing great satire on Ai companies with a hardly modified “Deep Thought” pastiche. Enjoyable all along and definitely a page turner that I read within three days..! And being strongly immersed in the current era, from the passing away of David Bowie to the dearful impact of Theresa May as home secretary. Presumably missing a heap of references to geek culture and subcultures, apart from Hitchhiker Guide to the Galaxy. And too many quotes to report, but some mentions of stats (“the Red Army had done a statistical analysis with demon traps just as they had with conventional minefields. The conclusions had been the same in both cases.” (p.50) and “Beverley climbed into the bath with a second-hand copy of Statistics for Environmental Science and Management” (p.69), which is a genuine book.) As often the end is a bit murky and a bit precipitated, but not enough to whine about. Recommended (conditional on having read the earliest ones in the series)!

a journal of the plague year [grey November reviews]

Posted in Books, Kids, Mountains, pictures, Travel with tags , , , , , , , , , , , , , , , , , , , , , , on November 21, 2020 by xi'an

Read Evil for Evil, K.J. Parker’s second tome in the Engineer trilogy, published in 2009! Surprisingly, I remembered enough of the first volume for the story to make sense and I enjoyed it, for the same reason I liked Sixteen ways to defend &tc., namely for its attention to logistics and medieval industry taking over the muscle-display of standard equivalents, plus the self-demeaning attitude of most characters, again a welcome change from the standards! The pace of the story sometimes get bogged down, though.

Slowly cooked pulled pork with a hellish amount of red peppers, meaning I ended up eating most of it by myself over a few days. Tried cauliflower risotto, and liked it. Took my mom to a nice restaurant in Caen, À Contre Sens, after an oyster breakfast with her on the quays of a nearby Channel harbour, with a surprise lunch based on local (Norman) products. Finding hardly anyone in the restaurant due to COVID regulations made the experience even more enjoyable. And such a difference from the previous Michelin we sampled this summer!

Wasted hours watching the US presidential vote counting slowly unraveling, computing & recomputing from the remaining ballots the required percentage of Biden’s votes towards catching up, and refreshing my NYT & Fivethirtyeight webpages way too often. And remain fazed by an electoral system stuck in a past when less than 50,000 men elected George Washington.

Cleaned up our vegetable patch after collecting the last tomatoes, pumpkins, and peppers. And made a few jars of green tomato jam, albeit not too sweet to be used as chutney!

Watched the TV series The Boys, after reading super-positive reviews in Le Monde and other journals. Which is a welcome satire on the endless sequence of super-heroes movies and series, by simply pushing on the truism that with super-powers does not come super-responsibility. Or even the merest hint of ethics. Plus some embarrassing closeness with the deeds and sayings of the real Agent Orange. Among the weaknesses, a definitive excess of blood and gore, ambiguous moral stands of the [far from] “good” guys who do not mind shooting sprees in the least, and some very slow episodes. Among the top items, the boat-meet-whale incident, “Frenchie” from Marseille almost managing a French accent when speaking some semblance of French, and Karl Urban’s maddening accent that’s a pleasure to listen even when I understand a sentence out of two, at best.