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The ergodic theorem and Gowers-Host-Kra seminorms without separability or amenability

The von Neumann ergodic theorem (the Hilbert space version of the mean ergodic theorem) asserts that if is a unitary operator on a Hilbert space, and is a vector in that Hilbert space, then one has in the strong topology, where is the -invariant subspace of, and is the orthogonal projection to. […]

On the inclusion of solutions in textbooks

From Jones, Game Theory: Mathematical Models of Conflict (link goes to Google Books), in the preface:"Some teachers may be displeased with me for including fairly detailed solutions to the problems, but I remain unrepentant [...] InShow More Summary

The probability of Asian-Hispanic food

From tomorrow's New York Times: an article on the growing prevalence of Asian-Hispanic fusion food in California. It's part of a series on the Census. Orange County, California is 17.87% Asian and 34.13% Hispanic -- so the majority of the population, 52.00%, is either Asian or Hispanic. Show More Summary

Another stylized fact bites the dust

According to economist Henry Farber (link from Dan Goldstein): In a seminal paper, Camerer, Babcock, Loewenstein, and Thaler (1997) find that the wage elasticity of daily hours of work New York City (NYC) taxi drivers is negative and conclude that their labor supply behavior is consistent with target earning (having reference dependent preferences). Show More Summary

Mistaken identity

Someone I know sent me the following email: The person XX [pseudonym redacted] who posts on your blog is almost certainly YY [name redacted]. So he is referencing his own work and trying to make it sound like it is a third party endorsing it. Show More Summary

Backup And Restore Procedures

Today’s exercise won’t ask you to write code. Let me tell you why. I bought a new printer to replace my old printer that had failed. Both the salesman at Micro Center and the printer manufacturer’s sales rep, who was in the store that day, assured me that the printer would work with my Debian […]

New research in tuberculosis mapping and control

Mapping and control. Or, as we would say, descriptive and causal inference. Jon Zelner informs os about two ongoing research projects: 1. TB Hotspot Mapping: Over the summer, I [Zelner] put together a really simple R package to do non-parametric...Show More Summary

How can teachers of (large) online classes use text data from online learners?

Dustin Tingley sends along a recent paper (coauthored with Justin Reich, Jetson Leder-Luis, Margaret Roberts, Brandon Stewart), which begins: Dealing with the vast quantities of text that students generate in a Massive Open Online Course (MOOC) is a daunting challenge. Show More Summary

Comparison of Bayesian predictive methods for model selection

This post is by Aki We mention the problem of bias induced by model selection in A survey of Bayesian predictive methods for model assessment, selection and comparison, in Understanding predictive information criteria for Bayesian models,...Show More Summary

Outside pissing in

Coral Davenport writes in the New York Times: Mr. Tribe, 73, has been retained to represent Peabody Energy, the nation’s largest coal company, in its legal quest to block an Environmental Protection Agency regulation that would cut carbon dioxide emissions from the nation’s coal-fired power plants... Show More Summary

And . . . our featured 2015 seminar speaker is . . . Thomas HOBBES!!!!!

Just in case you’ve forgotten where this all came from: This came in the departmental email awhile ago: CALL FOR APPLICATIONS: LATOUR SEMINAR — DUE DATE AUGUST 11 (extended) The Brown Institute for Media Innovation, Alliance (Columbia...Show More Summary

Information and Entropy in Biological Systems

You can join a workshop on entropy and information in biological systems, virtually, by watching the streaming video.

Pounds, Shillings, Pence

Mixed-radix number systems have a base, or radix, that varies at each position. For instance, the old-style British pounds, shillings and pence form a mixed-radix system where there are twelve pence in a shilling and twenty shillings in a pound, and calendars form a mixed-radix system where there are sixty seconds in a minute, sixty […]

Five Quickies

1. Reflexive completion. 2. Mathematicians accepting and declining overtures from GCHQ. 3. The Euler characteristic of an algebra. 4. Review of Nick Gurski's higher categories book. 5. Are lectures the best way to teach?

The championship! Thomas Hobbes vs. Philip K. Dick

OK, since this is the final round, you’re allowed to make as many Calvin and Hobbes jokes and as many dick jokes as you want. These two guys have been through a lot together. To get here, Hobbes defeated, in order, Larry David, Leo Tolstoy, Chris Rock, Ed Wood, and Miguel de Cervantes; while Dick […] The post The championship! Thomas Hobbes vs. Show More Summary

But when you call me Bayesian, I know I’m not the only one

Textbooks on statistics emphasize care and precision, via concepts such as reliability and validity in measurement, random sampling and treatment assignment in data collection, and causal identification and bias in estimation. But how...Show More Summary

Philip K. Dick (2) vs. George Carlin (2); Hobbes advances

For yesterday’s semifinal, I was all ready to go with this argument by Zbicyclist in favor of Cervantes: For someone who wasn’t writing in English, he’s credited with a fair number of English catchphrases. Let’s bring the old guy back to life and see what else he’s got. Show More Summary

This is why I’m a political scientist and not a psychologist

I can understand how people can hold all sorts of wacked-out political views (after all, in the past, people have supported ideas as crazy as abolitionism, polygamy, monarchy, and the nationalization of the means of production), but certain things in psychology just continue to baffle me, even though I know they’re true. Show More Summary

The Final Four: Cervantes, Hobbes, Dick, Carlin! Today’s semifinal: Miguel de Cervantes (2) vs. Thomas Hobbes

We’re nearing the end! Yesterday‘s winner was decided based on several Carlin quotes. From Paul, a great line on Muhammad Ali: He said, ‘No, that’s where I draw the line. I’ll beat ‘em up, but I don’t want to kill ‘em.’ And the government...Show More Summary

Stan meetup in NYC on Tuesday

The next Stan meetup in NYC is on Tuesday, 4/7/2015. If you have installation issues, modeling trouble, or just want to pick some of the developers’ brains, show up. Free. Registration required:   P.S. Show More Summary

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