Archive for The New York Times

another viral math puzzle

Posted in Books, Kids, R, University life with tags , , , , , , , on May 25, 2015 by xi'an

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


With presumably the operation ordering corresponding to


although this is not specified in the question. Which amounts to


and implies that c divides b and i divides gxh. Rather than pursing this analytical quest further, I resorted to R coding, checking by brute force whether or not a given sequence was working.

if (ord[1]+(13*ord[2]/ord[3])+ord[4]+
ord[9])-10==66) return(ord)}

I then applied this function to all permutations of {1,…,9} [with the help of the perm(combinat) R function] and found the 128 distinct solutions. Including some for which b:c is not an integer. (Not of this obviously gives a hint as to how a 8-year old could solve the puzzle.)

As pointed out in a comment below, using the test == on scalars is a bad idea—once realising some fractions may be other than integers—and I should thus replace the equality with an alternative that bypasses divisions,


leading to the overall R code

for (t in 1:factorial(9)){
  if (a[1]>0) sol=rbind(sol,a)}

and returning the 136 different solutions…

back from New York

Posted in Kids, pictures, Statistics, Travel, University life with tags , , , , , , , , , on April 5, 2015 by xi'an

ColumbiaA greatly enjoyable [if a wee bit tight] visit to Columbia University for my  seminar last Monday! (And a reasonably smooth trip if I forget about the screaming kids on both planes…!) Besides discussing with several faculty on our respective research interests, and explaining our views on replacing Bayes factors and posterior probabilities, views that were not strongly challenged by the seminar audience, maybe because it sounded too Bayesiano-Bayesian!, I had a great time catching up (well, almost!) with Andrew, running for one hour by the river both mornings, and even biking—does not feel worse than downtown Paris!—with Andrew a few miles to a terrific tiny Mexican restaurant in South Bronx, El Atoradero where I had a home-made tortilla (or pupusa) filled bexmexwith beans and covered with hot chorizo! (The restaurant was selected as the 2014 best Mexican restaurant in New York City by The Village Voice, whatever that means. And also has a very supportive review in The New York Times.) It was so good I (very exceptionally) ordered a second serving of spicy pork huarache, which was almost as good. And kept me well-fed till the next day, when I arrived in Paris. And with enough calories to fight the cold melted snow that fell when biking back to the office at Columbia. I also had an interesting morning in a common room at Columbia, working next to graduate students and hearing their conversations about homeworks and advisors (nothing to gossip about as their comments were invariably laudatory!, maybe because they suspected me of being a mole!)

Domaine de Mortiès [in the New York Times]

Posted in Mountains, Travel, Wines with tags , , , , , , , , , , , , , on March 7, 2015 by xi'an


“I’m not sure how we found Domaine de Mortiès, an organic winery at the foothills of Pic St. Loup, but it was the kind of unplanned, delightful discovery our previous trips to Montpellier never allowed.”

Last year,  I had the opportunity to visit and sample (!) from Domaine de Mortiès, an organic Pic Saint-Loup vineyard and winemaker. I have not yet opened the bottle of Jamais Content I bought then. Today I spotted in The New York Times a travel article on A visit to the in-laws in Montpellier that takes the author to Domaine de Mortiès, Pic Saint-Loup, Saint-Guilhem-du-Désert and other nice places, away from the overcrowded centre of town and the rather bland beach-town of Carnon, where she usually stays when visiting. And where we almost finished our Bayesian Essentials with R! To quote from the article, “Montpellier, France’s eighth-largest city, is blessed with a Mediterranean sun and a beautiful, walkable historic centre, a tourist destination in its own right, but because it is my husband’s home city, a trip there never felt like a vacation to me.” And when the author mentions the owner of Domaine de Mortiès, she states that “Mme. Moustiés looked about as enthused as a teenager working the checkout at Rite Aid”, which is not how I remember her from last year. Anyway, it is fun to see that visitors from New York City can unexpectedly come upon this excellent vineyard!

would you wear those tee-shirts?!

Posted in Kids, pictures with tags , , , , , on January 25, 2015 by xi'an

Here are two examples of animal “face” tee-shirts I saw advertised in The New York Times and that I would not consider wearing. At any time.

high spirits

Posted in Books, pictures, Wines with tags , , , , , , on November 30, 2014 by xi'an

no more car talk

Posted in Books, Kids, Travel with tags , , , , , on November 9, 2014 by xi'an

When I first came went to the US in 1987, I switched from listening to the French public radio to listening to NPR, the National Public Radio network. However, it was not until I met both George Casella and Bernhard Flury that I started listening to “Car Talk”, the Sunday morning talk-show by the Magliozzi brothers where listeners would call and expose their car problem and get jokes and sometime advice in reply. Both George and Bernhard were big fans of the show, much more for the unbelievable high spirits it provided than for any deep interest in mechanics. And indeed there was something of the spirit of Zen and the art of motorcycle maintenance in that show, namely that through mechanical issues, people would come to expose deeper worries that the Magliozzi brothers would help bring out, playing the role of garage-shack psychiatrists…Which made me listen to them, despite my complete lack of interest in car, mechanics and repair in general.

One of George’s moments of fame was when he wrote to the Magliozzi brothers about Monty Hall’s problem, because they had botched their explanation as to why one should always change door. And they read it on the air, with the line “Who is this Casella guy from Cornell University? A professor? A janitor?” since George had just signed George Casella, Cornell University. Besides, Bernhard was such a fan of the show that he taped every single morning show, that he would later replay on long car trips (I do not know how his familly enjoyed the exposure to the show, though!). And so happened to have this line about George on tape, that he sent him a few weeks later… I am reminiscing all this because I saw in the NYT today that the older brother, Tom Magliozzi, had just died. Some engines can alas not be fixed… But I am sure there will be a queue of former car addicts in some heavenly place eager to ask him their question about their favourite car. Thanks for the ride, Tom!

latest interviews on the philosophy of religion(s)

Posted in Books, Kids with tags , , , , , , , , , , on November 1, 2014 by xi'an

“But is the existence of God just a philosophical question, like, say, the definition of knowledge or the existence of Plato’s forms?” Gary Gutting, NYT

Although I stopped following The Stone‘s interviews of philosophers about their views on religion, six more took place and Gary Gutting has now closed the series he started a while ago with a self-interview. On this occasion, I went quickly through the last interviews, which had the same variability in depth and appeal as the earlier ones. A lot of them were somewhat misplaced in trying to understand or justify the reasons for believing in a god (a.k.a., God), which sounds more appropriate for a psychology or sociology perspective. I presume that what I was expecting from the series was more a “science vs. religion” debate, rather than entries into the metaphysics of various religions… Continue reading


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