## a very quick Riddle

Posted in Books, Kids, pictures, R with tags , , , , , , on January 22, 2020 by xi'an

A very quick Riddler’s riddle last week with the question

Find the (integer) fraction with the smallest (integer) denominator strictly located between 1/2020 and 1/2019.

and the brute force resolution

```for (t in (2020*2019):2021){
a=ceiling(t/2020)
if (a*2019<t) sol=c(a,t)}
```

leading to 2/4039 as the target. Note that

$\dfrac{2}{4039}=\dfrac{1}{\dfrac{2020+2019}{2}}$

## Hastings at 50, from a Metropolis

Posted in Kids, pictures, Running, Travel with tags , , , , , , , , , , , , , , , , , , , , , , on January 4, 2020 by xi'an

A weekend trip to the quaint seaside city of Le Touquet Paris-Plage, facing the city of Hastings on the other side of the Channel, 50 miles away (and invisible on the pictures!), during and after a storm that made for a fantastic watch from our beach-side rental, if less for running! The town is far from being a metropolis, actually, but it got its added surname “Paris-Plage” from British investors who wanted to attract their countrymen in the late 1800s. The writers H.G. Wells and P.G. Wodehouse lived there for a while. (Another type of tourist, William the Conqueror, left for Hastings in 1066 from a wee farther south, near Saint-Valéry-sur-Somme.)

And the coincidental on-line publication in Biometrika of a 50 year anniversary paper, The Hastings algorithm at fifty by David Dunson and James Johndrow. More of a celebration than a comprehensive review, with focus on scalable MCMC, gradient based algorithms, Hamiltonian Monte Carlo, nonreversible Markov chains, and interesting forays into approximate Bayes. Which makes for a great read for graduate students and seasoned researchers alike!

## start of 2020

Posted in Kids, Mountains, pictures, Travel with tags , , , , , on January 1, 2020 by xi'an

## emergence [jatp]

Posted in Mountains, pictures, Travel, University life with tags , , , , , , , on December 11, 2019 by xi'an

## Korean trip

Posted in Mountains, Running, Statistics, Travel, University life with tags , , , , , , , , , , , , , on November 24, 2019 by xi'an

A fairly short but exciting trip to Seoul and to the Fall meeting of the Korean Statistical Society there. Plus giving a seminar at Seoul National University, where I stayed and enjoyed its beautiful campus surrounded by hills painted in the flamboyant reds and yellows of trees. Running to the top of Gwanaksan in the early morning, with some scrambling moments, was a fantastic beginning for the day! Although it was quite unintentional Sacha Tsybakov from CREST happened to be another invited speaker at the meeting (along with Regina Liu from Rutgers, whom I was also met in Salzburg two months ago) and we had a nice stroll together on the University of Seoul campus during a break in the sessions, gaining another view of the city from the top of the Bukhasan mountain. The talk I gave there on the asymptotics of ABC happened to be more attended than my tutorial lecture delivered at the beginning of JSM in Denver this summer. I am thus quite grateful to the organisers for their invitation and this opportunity to meet Korean statisticians and to get a glimpse of Korean culture and cuisine!

## art brut

Posted in Kids, Travel with tags , , , , , on November 17, 2019 by xi'an

## Gyeongbokgung palace [jatp]

Posted in Statistics with tags , , , , , , , on November 10, 2019 by xi'an