# Posts

### October 02, 2014

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12:00 AM | Clustering of bigram frequencies

Rick Wicklin at the SAS blog writes on the frequency of bigrams in an English corpus. In English: how often does a pair of letters, such as “TH” or “QZ”, appear in English text? This is a follow-up to a previous post on the frequency of letters in an English corpus and builds on an […]

### October 01, 2014

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While it took quite a while (!), with several visits by three of us to our respective antipodes, incl. my exciting trip to Melbourne and Monash University two years ago, our paper on ABC for state space models was arXived yesterday! Thanks to my coauthors, Gael Martin, Brendan McCabe, and Worapree Maneesoonthorn, I am very […]

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https://twitter.com/ulaulaman/status/517303481565458432 by @ulaulaman about #Nash equilibria and their role in collective behavior The Nash equilibrium is an important tool in game theory: [It] is a solution concept of a non-cooperative game involving two or more players, in which each player is assumed to know the equilibrium strategies of the other players, and no player has anything to gain by changing only their own strategy. If each player has chosen a strategy and no player can benefit
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1:06 PM | Notices of the AMS is killing it

I am somewhat surprised to hear myself say this, but this month’s Notices of the AMS is killing it. Generally speaking I think of it as rather narrowly focused but things seem to be expanding and picking up. Scanning the list of editors, they do seem to have quite a few people that want to […]

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The (presumably) final article arising from the Polymath8 project has now been uploaded to the arXiv as “The “bounded gaps between primes” Polymath project – a retrospective“. This article, submitted to the Newsletter of the European Mathematical Society, consists of personal contributions from ten different participants (at varying levels of stage of career, and intensity […]

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3:09 AM | Linkage for the end of September

Algomation animated algorithms (G+)Rush hour video, or, what our robot-driven future will be like (G+)The Washington Post rants about those evil student pirates, but neglects to mention the free alternatives (G+)A song video about knots, from the low-dimensional topology blog (G+)Fun hex grid facts, via MF (G+)SODA 2015 accepted papers (G+)KaTeX, a lobotomized but fast web math renderer (G+)Against laptops in lectures, via MF (G+)David Wade’s ‘Fantastic Geometry’ – The
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The Major League Baseball postseason is starting just as I write this. From the National League, we have Washington, St. Louis, Pittsburgh, Los Angeles, and San Francisco. From the American League, we have Baltimore, Kansas City, Detroit, Los Angeles (Anaheim), and Oakland. These match up pretty well geographically, and this hasn’t gone unnoticed: see for […]

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Some of my favorite conversations are about prediction and its limits. For some, this is purely a practical topic, but for me it is a deeply philosophical discussion. Understanding the limits of prediction can inform philosophy of science, mind, and even questions of free-will. As such, I wanted to share with you a World Science […]

### September 30, 2014

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Today, we arXived a second version of our paper on ABC model choice with random forests. Or maybe [A]BC model choice with random forests. Since the random forest is built on a simulation from the prior predictive and no further approximation is used in the process. Except for the computation of the posterior [predictive] error […]

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8:47 PM | Ritratti: Winifred Edgerton Merrill

Winifred Edgerton Merrill fu la prima americana ad ottenere un dottorato in matematica presso la Columbia University nel 1886. Nella sua tesi sviluppò una rappresentazione geometrica degli infinitesimi in diversi sistemi di coordinate, utilizzando lo jacobiano per per derivare le trasformazioni tra gli integrali nei diversi sistemi.Tra matematica e astronomiaNata a Ripon, nel Wisconsin, il 24 settembre del 1862 da Emmet e Clara Edgerton, si trasferisce con la famiglia a New York intorno
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Kelly S.E. & Rozner S.A. (2012). Winifred Edgerton Merrill: "She Opened the Door", Notices of the American Mathematical Society, 59 (04) 504-512. DOI: http://dx.doi.org/10.1090/noti818

Citation

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2:52 PM | The chocolate factory gone up in smoke

There was a major fire near my house yesterday with many fire-engines rushing by and a wet smoke smell lingering by the whole night. As I found out during my early morning run, the nearby chocolate factory had completely burned. Actually, sixteen hours after the beginning of the fire, the building was still smouldering, with […]

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Not sure if you’ve seen this recent New York Times article entitled Learning to Love Criticism, but go ahead and read it if you haven’t. The key figures: …76 percent of the negative feedback given to women included some kind of personality criticism, such as comments that the woman was “abrasive,” “judgmental” or “strident.” Only […]

### September 29, 2014

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11:47 PM | Power laws and wealth

From Alison Griswold at Slate, reporting on the Wealth-X and UBS billionaire census (warning: obnoxious auto-playing music at the second link): “The typical billionaire has a net worth of $3.1 billion.” Does “typical” mean mean? or median? It appears that “mean” is intended, because the front page of this census says there are 2,325 billionaires […]

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This is a book I carried away from JSM in Boston as the Oxford University Press representative kindly provided my with a copy at the end of the meeting. After I asked for it, as I was quite excited to see a book linking Jorge Luis Borges’ great Library of Babel short story with mathematical […]

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6:40 PM | Wouldn’t trade places

Last week at the Heidelberg Laureate Forum, I was surrounded by the most successful researchers in math and computer science. The laureates had all won the Fields Medal, Abel Prize, Nevanlinna Prize, or Turing Award. Some had even won two of these awards. I thought about my short academic career [1]. If I had been […]

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La matematica, in particolare la geometria, è una disciplina visualizzabile, e questa possibilità può essere sfruttata per avvicinarla agli studenti di ogni ordine e grado. Docsity ha recentemente pubblicato una serie di gif animate utili proprio allo scopo, trovate un po' qua e là lungo il web.Una prima gif animata è quella relativa al completamento del quadrato, argomento un po' ostico per molti studenti: La gif successiva, invece, può utilmente
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1:03 PM | Chameleon models

Here’s an interesting paper I’m reading this morning (hat tip Suresh Naidu) entitled Chameleons: The Misuse of Theoretical Models in Finance and Economics written by Paul Pfleiderer. The paper introduces the useful concept of chameleon models, defined in the following diagram: Pfleiderer provides some examples of chameleon models, and also takes on the Milton Friedman argument that […]

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12:30 PM | Another Reason to Love the Number Seven

The world’s favorite number is seven, at least if the result of a poll conducted by Alex Bellos is to be believed. Some people like it because it is prime, some because they have a lot of sevens in...
-- Read more on ScientificAmerican.com

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10:30 AM | CERN's 60th Birthday

http://t.co/zU9b7V4idL by @ulaulaman about #CERN60 The day to celebrate CERN's birthday is arrived: The convention establishing CERN was ratified on 29 September 1954 by 12 countries in Western Europe. The acronym CERN originally stood in French for Conseil Européen pour la Recherche Nucléaire (European Council for Nuclear Research), which was a provisional council for setting up the laboratory, established by 12 European governments in 1952. The acronym was retained for the new
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6:08 AM | Scrupoli

Doris Mårtensson tornò a casa la sera di sabato venti aprile.Adesso erano le otto del lunedì mattina, e lei se ne stava davanti al grande specchio della camera da letto a rimirare la sua tintarella e pensava a quanto invidiosi sarebbero stati i suoi colleghi. Aveva un brutto livido provocato da un succhioto sulla coscia destra e due sul seno sinistro. Mentre si allacciava il reggiseno, pensò che forse, per una settimana o dieci giorni, sarebbe stato il caso di evitare
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3:16 AM | University of Würzburg graffiti

I neglected to pack my camera and its new lens with me for the trip to GD (oops), and anyway most of the time the weather wasn't very conducive to photography. But I did take a couple of cellphone snapshots of graffiti/murals on the University of Würzburg campus. This one, if Google translate is to be believed, proclaims Würzburg as the city of young researchers; it's on the wall of the Mensa where we ate lunch every day.And here's some advice to the students starting the new term,
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### September 28, 2014

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10:14 PM | future of computational statistics

I am currently preparing a survey paper on the present state of computational statistics, reflecting on the massive evolution of the field since my early Monte Carlo simulations on an Apple //e, which would take a few days to return a curve of approximate expected squared error losses… It seems to me that MCMC is […]

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5:43 PM | Foucault and the pendulum

http://t.co/AphFwEZfQ2 #foucaultpendulum #physics #earthrotation The first public exhibition of a Foucault pendulum took place in February 1851 in the Meridian of the Paris Observatory. A few weeks later Foucault made his most famous pendulum when he suspended a 28 kg brass-coated lead bob with a 67 meter long wire from the dome of the Panthéon, Paris. The plane of the pendulum's swing rotated clockwise 11° per hour, making a full circle in 32.7 hours. The original bob used in 1851
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Is D. C. Statehood a matter of civil rights?, by Andrew Giambrone in The Atlantic I know, what does this have to do with math? Well, you could read Chris Wilson’s article for Slate on Puerto Rico statehood back in 2010, in which he writes about possible flag designs; we’d probably end up going with […]

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1:25 PM | Il (non) carnevale della fisica #1

Cos'è la fisica? Vediamo cosa si legge su it.wiki: La fisica è la scienza della natura nel senso più ampio. Il termine "fisica" deriva dal neutro plurale latino physica, a sua volta derivante dal greco τὰ φυσικά [tà physiká], ovvero "le cose naturali" e da φύσις [physis], "natura".Scopo della fisica è lo studio dei fenomeni naturali, ossia di tutti gli eventi che possano essere
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As one goes through more advanced expositions of quantum physics, the concept of action is gradually given more importance, with it being considered a fundamental piece in some introductions to Quantum Field Theory (Zee, 2003) through the use of the path integral approach. The basic idea behind using the action is to assign a number […]

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4:05 AM | Squares and Motzkins

Greg Smith gave an awesome colloquium here last week about his paper with Blekherman and Velasco on sums of squares. Here’s how it goes. You can ask: if a homogeneous degree-d polynomial in n variables over R takes only non-negative values, is it necessarily a sum of squares? Hilbert showed in 1888 that the answer […]

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1:29 AM | Report from Graph Drawing

I'm currently in the process of returning* from Würzburg, Germany, where I attended the 22nd International Symposium on Graph Drawing (GD 2014) and was one of the invited speakers at the associated EuroGIGA/CCC Ph.D. school on graph drawing.The format for the Ph.D. school was three one-hour lectures in the morning and three hours of working on exercises in the afternoon, for two days. My contribution was a high-level overview of graph drawing methods that involve curves (an updated version
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### September 27, 2014

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10:14 PM | redshirts

“For the first nine years of its existence, aside from being appointed the flagship, there was nothing particularly special about it, from a statistical point of view.” A book I grabbed at the last minute in a bookstore, downtown Birmingham. Maybe I should have waited this extra minute… Or picked the other Scalzi’s on the […]

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9:33 PM | 100 Followers

OMG!! Thank you sooo soo so much! This made my day, week, everything! I am so happy to see that so many of you like and mostly want to see more of my math-love. As maybe you already know I … Continue reading →