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A Springer book published in conjunction with the great BAYSM 2014 conference in Wien last year has now appeared. Here is the table of contents: Bayesian Survival Model Based on Moment Characterization by Arbel, Julyan et al. A New Finite Approximation for the NGG Mixture Model: An Application to Density Estimation by Bianchini, Ilaria Distributed […]

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8:08 PM | Git for Philosophers, Packaged with PDF

If you want to print the “Git for philosophers” piece, I made a release of the Git version with PDF and HTML versions. Here’s the PDF of Git for philosophers.

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2:30 PM | The Halting Problem For Linear Machines

A small idea before the fireworks show Thoralf Skolem was a mathematician who worked in mathematical logic, set theory, and number theory. He was the only known PhD student of Axel Thue, whose Thue systems were an early word-based model of computation. Skolem had only one PhD student, Öystein Ore, who did not work in […]

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12:18 PM | snapshot from Boston

Filed under: pictures, Travel Tagged: adds, Boston, Clarex, Massachusset, métro

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9:50 AM | Συμμετρική κατάσταση

Γνωρίζουμε πολύ καλά ότι αν είναι τα συνηθισμένα διανύσματα βάσης στο επίιπεδο τότε κάθε διάνυσμα μπορεί να γραφεί ως: . Μπορεί δηλ. να γραφεί το ως γραμμικός συνδυασμός των όπου οι συντελεστές είναι απλά τα εσωτερικά γινόμενα με τα διανύσματα αυτά. Το ίδιο φυσικά ισχύει αν […]

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6:25 AM | A non-logical cognitive phenomenon

This is from an early version of Chapter 7 and from my 2009 presentation on avatars at the conference Two Streams in the Philosophy of Mathematics organized by David Corfield and Brendan Larvor. Some of the first half has been preserved on p. 215 and there is a hint of the remainder on p. 201. […]

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4:46 AM | Beware Wishful Thinking!

The remainder of this post has been removed, as having been based on confusion of a very-connected space with an action of $n!$ and an $n!$-equivariant image of it — the latter is very like a $\mathbf{B}n!$, and not very-connected.

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1:00 AM | A Celebration of Independence

Yesterday marked the second anniversary of my blog, and today is the 239th birthday of the U.S. In celebration of Independence Day, I want to explain what matroids are. Matroids were invented by Hassler Whitney (and independently by Takeo Nakasawa) to abstract the notion of linear independence from vector spaces to a much more general […]

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12:59 AM | The axiom of determinacy for small sets

I should like to argue that the axiom of determinacy is true for all games having a small payoff set. In particular, the size of the smallest non-determined set, in the sense of the axiom of determinacy, is the continuum; … Continue reading →

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While I now try to abstain from participating to the Cross Validated forum, as it proves too much of a time-consuming activity with little added value (in the sense that answers are much too often treated as disposable napkins by users who cannot be bothered to open a textbook and who usually do not exhibit […]

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5:00 PM | Gli enigmi di Coelum: Palomar Cube

Continua la serie degli enigmi matematici da me pubblicati sulla rivista Coelum Astronomia. Nel numero di dicembre 2013 parlai di cubi, o meglio di cubi 3 × 3 × 3: un oggetto fondamentale, direi, nella storia della matematica ricreativa. Alzi la mano chi non ha mai provato, almeno una volta, a mettere in ordine il celeberrimo cubo di Rubik, geniale
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por Agustín Moreno En pos de contextualización, este post surgió de una discusión sobre matemática y afines con el sambita, mientras nos partiamos la boca con tremendos churrascos y un vinito en algún bar perdido de Paris. El tipo queria saber para que quiere uno las curvas holomorfas esas de las que tanto se ha […]

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por Agustín Moreno En pos de contextualización, este post surgió de una discusión sobre matemática y afines con el sambita, mientras nos partiamos la boca con tremendos churrascos y un vinito en algún bar perdido de Paris. El tipo queria saber para que quiere uno las curvas holomorfas esas de las que tanto se ha […]

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3:07 PM | The High Cost of Conferences

At some point, I'm convinced the "conference structure" is going to fall apart.Case in point -- I haven't bought my tickets yet for SIGCOMM because, unless I'm missing something, a schedule isn't up yet, and unfortunately, because ACM has scheduled a SIG chair meeting overlapping with SIGCOMM (which I don't understand also, but perhaps beside the point), I want to see what's going on when at the conference to plan my timing. 6+ weeks out, round trip tickets from Boston to London […]

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12:18 PM | “UK outmoded universities must modernise”

[A rather stinky piece in The Guardian today, written by a consultant self-styled Higher Education expert… No further comments needed!] “The reasons cited for this laggardly response [to innovations] will be familiar to any observer of the university system: an inherently conservative and risk-averse culture in most institutions; sclerotic systems and processes designed for a […]

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11:46 AM | Signed incidence matrices in Sagemath

Let be a graph with an edge orientation. This means that we are given , where V is the set of vertices and E a set of ordered pairs of distinct vertices representing the edges, and, for each edge an “orientation”. Simply put, an orientation on $\latex \Gamma$ is a list of length |E| consisting […]

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11:39 AM | Serveurs SVN

Subversion (SVN) est un outil informatique qui permet de gérer la collaboration sur des documents et en particulier des textes. Il automatise (jusqu’à un certain point!) la mise en commun des modifications et systématise l’archivage. Son utilisation nécessite un logiciel sur la machine de chaque collègue (“client svn”) mais aussi un logiciel (“serveur svn”) tournant […]

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11:27 PM | Artificial life which can be programmed

Artificial life which can be programmed __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________Filed under: Uncategorized Tagged: artificial intelligence, artificial life, chemlambda

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11:19 PM | Clutters I

I have been trying to firm up my feeling for the theory of clutters. To that end, I have been working through proofs of some elementary lemmas. For my future use, as much as anything else, I will post some … Continue reading →

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10:15 PM | Kamiltonian Monte Carlo [no typo]

Heiko Strathmann, Dino Sejdinovic, Samuel Livingstone, Zoltán Szabó, and Arthur Gretton arXived paper about Kamiltonian MCMC generated comments from Michael Betancourt, Dan Simpson and myself, which themselves induced the following reply by Heiko, detailed enough to deserve a post of its own. Adaptation and ergodicity. We certainly agree that the naive approach of using a […]

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8:46 PM | Pak on combinatorics videos

I’m a little late to this, but Igor Pak has a list of combinatorics videos (of lectures and seminars) and an explanation of why you should watch them, why you should let people make videos of you, and so on. … Continue reading →

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6:59 PM | Tunisia

Tunisia has been in the news for the wrong reasons. I sincerely hope that the people of this beautiful and hospitable country are not seriously harmed by the recent terrorist outrages. The best I can do to show my solidarity … Continue reading →

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12:18 PM | R brut

Filed under: Kids, pictures, R, Statistics, University life Tagged: cex, pch, plot, R

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6:13 AM | Congratulations

… to Robert Schumacher, who passed his PhD viva this week. He has some revisions to do after a well-earned holiday. And thanks for the flowers!

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5:20 AM | A note on products of sequential fans

Two posts (the previous post and this post) are devoted to discussing the behavior of countable tightness in taking Cartesian products. The previous post shows that countable tightness behaves well in the product operation if the spaces are compact. In … Continue reading →

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In the previous two posts, we discuss the definitions of the notion of tightness and its relation with free sequences. This post and the next post are to discuss the behavior of countable tightness under the product operation. In this … Continue reading →

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Non prevedevo di scrivere la versione italiana di un post sull'ultima news proveniente dal RHIC, ma mi è stato gentilmente chiesto, e provvedo ben volentieri. Inizio, però, con un piccolo cappello, alla fine del quale saprete che c'è anche un piccolissimo pezzetto (il doppio diminutivo è perché i firmatari del papero su arXiv sono veramente tanti) d'Italia in questa interessante scoperta.Tutto nasce da un post, nel flusso twittero, di Annalisa Arci, in cui racconta, in maniera e con un […]

Belavina A.A., Polyakova A.M., Schwartza A.S. & Tyupkina Y.S. (1975). Pseudoparticle solutions of the Yang-Mills equations, Physics Letters B, 59 (1) 85-87. DOI: 10.1016/0370-2693(75)90163-X

Hooft G.'. (1976). Symmetry Breaking through Bell-Jackiw Anomalies, Physical Review Letters, 37 (8) DOI: 10.1103/PhysRevLett.37.8

Hooft G.'. (1976). Computation of the quantum effects due to a four-dimensional pseudoparticle, Physical Review D, 14 DOI: 10.1103/PhysRevD.14.3432

Fukushima K., Kharzeev D.E. & Warringa H.J. (2008). The Chiral Magnetic Effect, Physics Review D, 78 (7) DOI: 10.1103/PhysRevD.78.074033

Kharzeev D.E. & Yee H.U. (2011). Chiral Magnetic Wave, Physical Review D, 83 DOI: 10.1103/PhysRevD.83.085007

STAR Collaboration (2015). Observation of charge asymmetry dependence of pion elliptic flow and the possible chiral magnetic wave in heavy-ion collisions, arXiv, arXiv: 1504.02175v2

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http://t.co/urnbKwoiSY by @ulaulaman about #neutrino #tau #Opera #particlephysics From the press release: The OPERA (Oscillation Project with Emulsion-tRacking Apparatus) international experiment at the National Institute for Nuclear Physics (INFN) Gran Sasso Laboratory (Italy) has detected the fifth occurrence of a tau neutrino. The neutrino started its flight at CERN as muon neutrino and, after traveling 730 km through the Earth, it arrived at Gran Sasso Laboratories showing up as a tau
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DONUT Collaboration (2001). Observation of Tau Neutrino Interactions, Physics Letters B, 504 (3) 218-224. DOI: 10.1016/S0370-2693(01)00307-0

OPERA Collaboration (2014). Observation of tau neutrino appearance in the CNGS beam with the OPERA experiment, Progress of Theoretical and Experimental Physics, 101C01 DOI: 10.1093/ptep/ptu132

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#abstract from #arXiv via @ulaulaman A couple of mathematical abstracts from arXiv: N. Karjanto (2015). Calculus teaching and learning in South Korea Jurnal Matematika Integratif 9(2): 179-193, 2013 arXiv: 1504.07803v1This article discusses an experience of teaching Calculus classes for the freshmen students enrolled at Sungkyunkwan University, one of the private universities in South Korea. The teaching and learning approach is a balance combination between the teacher-oriented traditional
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N. Karjanto (2015). Calculus teaching and learning in South Korea, Jurnal Matematika Integratif 9(2): 179-193, 2013, arXiv: 1504.07803v1

Sandor Kiss (2015). Educational Challenges of Rubik's Cube, X Workshop on Particle Correlations and Femtoscopy, arXiv: 1505.00750v1

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Come scrivono i Rudi Mathematici, "John Forbes Nash se n'è andato". C'è poco da dire in situazioni del genere, se non provare a scrivere, magari della sua matematica. Ho provato a farlo in modi piuttosto indiretti, lo faccio oggi in un modo un po' più diretto.Uno dei risultati più importanti di John Nash è la scoperta dell'esistenza degli equilibri che portano il suo nome all'interno dei giochi non collaborativi. La teoria di base su questo genere di giochi prende le mosse da due suoi […]

Nash, J. (1950). Equilibrium points in n-person games, Proceedings of the National Academy of Sciences, 36 (1) 48-49. DOI: 10.1073/pnas.36.1.48

Nash J. (1951). Non-Cooperative Games, The Annals of Mathematics, 54 (2) 286-295. DOI: http://dx.doi.org/10.2307/1969529

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http://t.co/gCOlKccELA about #IngeLehmann #EarthCore #theCore #geophysics Inge Lehmann was a Danish seismologist and geophysicist. Using seismic data, she discovered the inner solid core of the Earth with some physical properties distinct from the outer liquid core: No rays emerged at epicentral distances between 112° and 154°. I then placed a smaller core inside the first core and let the velocity in it be larger so that a reflection would occur when the rays through the larger core met it.
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Lehmann, I. (1987). Seismology in the days of old, Eos, Transactions American Geophysical Union, 68 (3) 33. DOI: 10.1029/EO068i003p00033-02

Bolt, B. (1994). Inge Lehmann, Physics Today, 47 (1) 61. DOI: 10.1063/1.2808386

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MindAfterMath tweeted: @MindAfterMath

Examples of the Binary Search Algorithm http://t.co/wQGgw9i3Nx #compsci #datascience #math #stem #mathchat

2015-07-05 05:34:53

simonjob tweeted: @simonjob

RT @mathslinks: Watch a 4 minute video introducing the new Lists feature on MathsLinks. https://t.co/AFmSciHWLg

2015-07-05 05:29:27

loronegro tweeted: @loronegro

Definitivamente el Hola está varios grados más abajo que el Alarma.

2015-07-05 04:17:22

loronegro tweeted: @loronegro

RT @Pajaropolitico: Zabludovsky, fundador (de los noticiarios de televisión abierta) en México/
...de la manipulación de la realidad...

2015-07-05 04:08:11

loronegro tweeted: @loronegro

Pareciera que el gobierno griego sí es verdaderamente de izquierda.
#OXI

2015-07-05 03:57:03

MindAfterMath tweeted: @MindAfterMath

2015-07-05 03:34:48

Mr_Ulrich_UW tweeted: @Mr_Ulrich_UW

RT @thereaIbanksy: you are more than your mistakes

2015-07-05 02:59:39

Mr_Ulrich_UW tweeted: @Mr_Ulrich_UW

2015-07-05 02:59:33

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