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Failure of the L^1 pointwise and maximal ergodic theorems for the free group

I’ve just uploaded to the arXiv my paper “Failure of the pointwise and maximal ergodic theorems for the free group“, submitted to Forum of Mathematics, Sigma. This paper concerns a variant of the pointwise ergodic theorem of Birkhoff, which asserts that if one has a measure-preserving shift map on a probability space, then for […]

New Alan Turing preprint on Arxiv!

Dan Kahan writes: I know you are on 30-day delay, but since the blog version of you will be talking about Bayesian inference in couple of hours, you might like to look at paper by Turing, who is on 70-yr delay thanks to British declassification...Show More Summary

The Revolution Will Not Be Formalized

My opinion about the future of computer-verified proof.

Categorifying the Magnitude of a Graph

See how there's a homology theory for graphs with magnitude as its Euler characteristic.

Bob Carpenter’s favorite books on GUI design and programming

Bob writes: I would highly recommend two books that changed the way I thought about GUI design (though I’ve read a lot of them): Jeff Johnson. GUI Bloopers. I read the first edition in book form and the second in draft form (the editor...Show More Summary

On deck this week

Mon: Bob Carpenter’s favorite books on GUI design and programming Tues: Bayesian inference: The advantages and the risks Wed: Objects of the class “Foghorn Leghorn” Thurs: “Physical Models of Living Systems” Fri: Creativity is the ability...Show More Summary

“Do we have any recommendations for priors for student_t’s degrees of freedom parameter?”

In response to the above question, Aki writes: I recommend as an easy default option real nu; nu ~ gamma(2,0.1); This was proposed and anlysed by Juárez and Steel (2010) (Model-based clustering of non-Gaussian panel data based on skew-t distributions. Show More Summary

Are you ready to go fishing in the data lake?

While Andrew is trying to get someone to make a t-shirt design “Gone fishing”, someone else thinks fishing is one of the “big data trends in 2015?. This advertisement by some company keeps re-appearing in my twitter feed. The post Are you ready to go fishing in the data lake? appeared first on Statistical Modeling, Causal Inference, and Social Science.

Apology to George A. Romero

This came in the email one day last year: Good Afternoon Mr. Gelman, I am reaching out to you on behalf of Pearson Education who would like to license an excerpt of text from How Many Zombies Do You Know? for the following, upcomingShow More Summary

Behind The Numbers: Food for Thought

When it comes to data, the language used to explain is often as important as the numbers. The USDA's estimates of where folks are eating is a prime example.

Marco Polo: I approve, so far

I finally got around to watching Marco Polo. This is perhaps surprising news, as anyone who knows me could guess this would be right up my alley: almost superhuman martial arts (at least in the promo material), an eastern setting, and a clash of nations … I’m on episode three, and I’m suprised to say […]

I actually think this infographic is ok

Under the heading, “bad charts,” Mark Duckenfield links to this display by Quoctrung Bui and writes: So much to go with here, but I [Duckenfield] would just highlight the bars as the most egregious problem as it is implied that the same number of people are in each category. Show More Summary

Convert Ratio To Decimal

Our exercise today is an interview question. Like all of our interview questions, it works better if you put some pressure on yourself to simulate the pressure of an interview; so, for today’s exercise you must complete your solution in fifteen minutes: Given two positive integers, a numerator and a denominator, and a third positive […]

Higher order interactions and SDM 2015

This year I'm one of the PC Chairs for SIAM Data Mining (along with Jieping Ye), and so I've been spending time in decidedly-not-sunny Vancouver. Being a PC Chair, or even being on a PC, is an exercise in constant deja vu: I hear a talk...Show More Summary

A remark on the lonely runner conjecture

The lonely runner conjecture is the following open problem: Conjecture 1 Suppose one has runners on the unit circle, all starting at the origin and moving at different speeds. Then for each runner, there is at least one time for which that runner is “lonely” in the sense that it is separated by a […]

The connection between varying treatment effects and the well-known optimism of published research findings

Jacob Hartog writes: I thought this article [by Hunt Allcott and Sendhil Mullainathan], although already a couple of years old, fits very well into the themes of your blog—in particular the idea that the “true” treatment effect is likely...Show More Summary

“I mean, what exact buttons do I have to hit?”

While looking for something else, I happened to come across this: Unfortunately there’s the expectation that if you start with a scientific hypothesis and do a randomized experiment, there should be a high probability of learning an enduring truth. Show More Summary

Numbers Noise: IP Addresses Near Limit

The U.S. is running out of Internet Protocol addresses. But this doesn't mean the Internet has reached its limit.

My talk at MIT this Thursday

When I was a student at MIT, there was no statistics department. I took a statistics course from Stephan Morgenthaler and liked it. (I’d already taken probability and stochastic processes back at the University of Maryland; my instructor in the latter class was Prof. Show More Summary

Number of the Day: $179.4 Million

Today's number, $179.4 million, comes courtesy of the auction house Christie's, which on Monday evening sold Picasso's "Women of Algiers (Version O)" to an anonymous telephone bidder.

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