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November 22, 2014

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11:14 PM | Challis Lectures
  I had a great time during this short visit in the Department of Statistics, University of Florida, Gainesville. First, it was a major honour to be the 2014 recipient of the George H. Challis Award and I considerably enjoyed delivering my lectures on mixtures and on ABC with random forests, And chatting with members […]
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10:41 PM | A temperature puzzle
Last Friday morning (the 14th) it was unseasonably cold in Atlanta. On the way to work I noticed my car’s display giving the following temperature readings: 28, 30, 32, 34, 36 – all in Fahrenheit. It somehow knew to avoid … Continue reading →
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1:30 PM | 11/22/14
1 * 1 * 2 * 2 * 1 = 4 Also: 1 * 1 / (2 + 2) = 1 / 4 Also: 1 * 1 * 2 / 2 = 1^4 Also: 1 + 1= 2 = 2 = 1 * √4
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12:16 PM | A HoTT PhD position in Ljubljana
I am looking for a PhD student in mathematics. Full tuition & stipend will be provided for a period of three years, which is also the official length of the programme. The topic of research is somewhat flexible and varies from constructive models of homotopy type theory to development of a programming language for a […]
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10:10 AM | Poynting wants to know how energy is transfered
The Poynting vector represents energy in the electromagnetic fields and is given by     Students often read it as the “pointing vector”, but Poynting was a person, not a direction. Here are his own words. A SPACE containing electric … Continue reading →
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9:23 AM | Interlude in St Andrews
A fortnight in St Andrews was intended to be a little rest after a busy few months. It didn’t work out that way. Several mathematical things which I will report on later, including a visit from my collaborator Celia Glass … Continue reading →
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12:57 AM | A general parity problem obstruction
Many problems and results in analytic prime number theory can be formulated in the following general form: given a collection of (affine-)linear forms , none of which is a multiple of any other, find a number such that a certain property of the linear forms are true. For instance: For the twin prime conjecture, one […]

November 21, 2014

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11:14 PM | a pile of new books
I took the opportunity of my weekend trip to Gainesville to order a pile of books on amazon, thanks to my amazon associate account (and hence thanks to all Og’s readers doubling as amazon customers!). The picture above is missing two  Rivers of London volumes by Ben Aaraonovitch that I already read and left at […]
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8:35 PM | Edición 5.8 Betty Scott del Carnaval de Matemáticas: 23-30 de noviembre
Sólo una breves líneas para recordaros que la próxima edición del Carnaval de Matemáticas, la Edición 5.8 Betty Scott, se celebrará del 23 al 30 de noviembre (vamos, la próxima semana) en el blog Tocamates.Esta edición estará dedicada a la matemática y estadística  americana Elizabeth Scott que el próximo 23 de noviembre cumpliría 97 años.Para participar en esta edición, hay que hacer lo de siempre:Publicar, entre el 23 y el 30 de noviembre algún contenido que […]
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6:39 PM | Hindley-Milner for chemlambda
 Some notes about Hindley-Milner in #chemlambda . It turns out that is pretty simple to do something very intuitive. The starting point is the mol file which encodes a graph molecule. Let me recall how this works. The ingredients of a molecule are some nodes, which have ports. Nodes can be red, green, yellow or … Continue reading Hindley-Milner for chemlambda →
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3:00 PM | Explore Longform with Writing 201
Explore longform writing in our newest Blogging U. course, Writing 201: Beyond the Blog Post. The fun starts Monday, December 1 -- learn more and register today!
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1:30 PM | 11/21/14
1 + 1 + (2 * 1) = 1 * 4 Also: 1 * 1 * 2 * 1 = 1 * √4
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1:18 PM | some LaTeX tricks
Here are a few LaTeX tricks I learned or rediscovered when working on several papers the past week: I am always forgetting how to make aligned equations with a single equation number, so I found this solution on the TeX forum of stackexchange, Namely use the equation environment and then an aligned environment inside. Or […]
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10:10 AM | Merton was on to Itó’s formula before it was cool
Judging from his published papers Merton was already expert at continuous time finance before the 1973 option pricing papers came out. A Digression on Itó Processes To apply the dynamic programming technique in a continuous-time model, the state variable dynamics … Continue reading →
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9:08 AM | ‘George Green’s Mathematical Influences’ — audio now available
I recently gave a public talk about George Green’s mathematical education and influences, the audio for which is now available online. Green attended Robert Goodacre’s school in Nottingham 1801-2 and took part in scientific culture in Nottingham, including at Bromley House Library, in the 1810s and 20s, before going to Cambridge in 1833. I speak... Read more »
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2:18 AM | New Series: Moduli of Riemann Surfaces
Though I’m not quite ready to start (next week!) I feel that, in the spirit of Jim getting back to the blogging and my continued promises, I’d announce my series now.  I’m going to start a detailed series on the … Continue reading →

November 20, 2014

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11:14 PM | not converging to London for an [extra]ordinary Read Paper
On December 10, I will alas not travel to London to attend the Read Paper on sequential quasi-Monte Carlo presented by Mathieu Gerber and Nicolas Chopin to The Society, as I fly instead to Montréal for the NIPS workshops… I am quite sorry to miss this event, as this is a major paper which brings […]
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7:20 PM | limbo IPA
Filed under: pictures, Travel, Wines Tagged: ÌPA, Limbo IPA, Long Trail Brewing Company, Maine, USA, Vermont
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6:34 PM | Upward closure in the toy multiverse of all countable models of set theory
$\newcommand\P{\mathbb{P}}\newcommand\Q{\mathbb{Q}}\newcommand\R{\mathbb{R}} \newcommand\of{\subset}\newcommand\cross{\times}$ I’d like to explain a topic from my recent paper G. Fuchs, J. D. Hamkins, J. Reitz, Set-theoretic geology, to appear in the Annals of Pure and Applied Logic. We just recently made the final revisions, and the paper … Continue reading →
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6:23 PM | The Geometry of Restricted Partitions
Last week, I attended the IMA Workshop on Geometric and Enumerative Combinatorics which was, hands down, the best conference I have ever attended. The speaker lineup was simply amazing and I return brimming with ideas for future projects and collaborations. I felt, therefore, particularly honored to be invited to speak in front of this audience, given that so many of my personal “academic heroes”, who I have cited so often, were present. Given these high stakes, I am delighted to […]
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1:30 PM | 11/20/14
1 + 1 = 2 + 0 = 1 * √4 Also: 1 + 1 + 2 + 0 = 1 * 4
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10:30 AM | La circunferencia de Conway
En muchas ocasiones hemos visto que la geometría en general, y la del triángulo en particular, nos puede proporcionar resultado preciosos a la par que inesperados. Éste es el caso del que os voy a mostrar en esta entrada, que además de ser una maravilla geométrica nos da la forma de construir la que en […]Entra en Gaussianos si quieres hacer algún comentario sobre este artículo, consultar entradas anteriores o enviarnos un mensaje.Construye tú también el […]
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10:10 AM | Metropolis inadvertently creates a major tool for statistics in a physics paper.
While trying to do Statistical Mechanics simulations a group of physicists at Los Alamos faced the problem of simulating from the canonical distribution. The method they created was generalized by Hastings to the become the Metropolis-Hastings workhorse of statistics. Notice … Continue reading →
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6:54 AM | What to do if a proof is psychologically uncomfortable?
Robert Thomason suggests the following in his article The classification of triangulated subcategories: The reader may find the indirectness of the proof of this useful corollary psychologically uncomfortable. If so, rather than dosing himself with a benzodiazepine, he may find relief in deducing Corollary 2.3 from the following criterion for equality of two classes in […]
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4:15 AM | On proof and progress in feminism
The recent allegations against several celebrities have led to a broader conversation on how we, as a society, don’t believe women. In a “he said, she said” situation, we trust the man and assume that the woman is either mistaken … Continue reading →
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3:26 AM | Two Versus Three
The role of 2 and 3 in mathematics Electrika source Margaret Farrar was the first crossword puzzle editor for The New York Times. Ken fondly recalls seeing her name while watching his father do the daily and weekly NYT puzzles—they were under Farrar’s byline as editor until 1969 when she retired from the Times. More […]

November 19, 2014

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11:36 PM | ANU hiring postdocs
Amnon Neeman has just put up an ad for two postdoctoral positions at the ANU. He says: “The successful applicants should have strong research interests and activities in or related to one of the following fields: Algebraic Geometry, Commutative Algebra, Representation Theory, Algebraic Topology, Algebraic K-Theory. Skills at applying the techniques of triangulated categories to […]
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11:14 PM | Bayesian evidence and model selection
Another arXived paper with a topic close to my interests, posted by Knuth et al. today. Namely, Bayesian model selection. However, after reading the paper in Gainesville, I am rather uncertain about its prospects, besides providing an entry to the issue (for physicists?). Indeed, the description of (Bayesian) evidence is concentrating on rough approximations, in […]
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6:46 PM | The Imitation Game
This season’s Hollywood math/physics extravangza is starting to come to an end. For coverage of the Breakthrough Prize ceremony, I enthusiastically recommend Michael Harris’s new piece at Slate which just appeared. The final high profile production, one promoted at the … Continue reading →
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5:16 PM | Math majors attacked by cognitive dissonance
In some situations you may have conflicting information from different sources about a subject.   The resulting confusion in your thinking is called cognitive dissonance. It may happen that a person suffering cognitive dissonance suppresses one of the ways of understanding in order to resolve the conflict.  For example, at a certain stage in learning English, […]
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