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Posts

May 26, 2015

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4:02 AM | Online Recommender Systems – How Does a Website Know What I Want?
“People you may know.” “Other products you may like.” “Customers Who Bought This Item Also Bought…” We’ve all seen these suggestions when browsing the web, be it on Facebook or Amazon or some other platform. But how do the sites … Continue reading →

May 25, 2015

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2:56 PM | John Nash (1928-2015)
John Nash and his wife Alicia died in a taxi accident, returning from the airport after he received the Abel prize in Norway. The public knew John Nash as the "Beautiful Mind" of book and screen, but we knew him as one of the great geniuses of the 20th century. Rakesh Vohra captures Nash's life and work, including his amazing letters to the NSA. I briefly met John Nash at some MIT alumni events in New Jersey when I lived there (even though neither of us were MIT undergrads). He would come […]
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10:08 AM | 42 and Douglas Adams
http://t.co/OYVsXcrpqm happy #towelday with @ulaulaman 42: properties and curiosities
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6:20 AM | John F. Nash, Jr. (1928-2015)
“呜呼,人和人的魂灵,是不相通的。” 这是John Nash的形象:他的公众知名度几乎完全基于A Beautiful Mind——一个数学家因为他的疯狂,而非他的理性,为世人所熟知。2010年冷泉港实验室授予Nash双螺旋奖章,理由是“Dr. Nash has used his influence as a public role model to become an active advocate for mental health issues”. 这也是John […]
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5:51 AM | A quick thought on Supernatural and some other tv shows
Just finished season 9 of Supernatural. You’ve got to give that show credit for being one of the few that *demands* a deus ex machina ending. Anything less, after all this fighting over who’s going to take God’s place and Castiel’s moments of mysterious grace, would be a let down. I can’t wait to see […]
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12:56 AM | From our “Philosophy of Statistics” session: APS 2015 convention
“The Philosophy of Statistics: Bayesianism, Frequentism and the Nature of Inference,” at the 2015 American Psychological Society (APS) Annual Convention in NYC, May 23, 2015: D. Mayo: “Error Statistical Control: Forfeit at your Peril”    S. Senn: :”‘Repligate’: reproducibility in statistical studies. What does it mean and in what sense does it matter?” For more […]

May 24, 2015

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9:57 PM | New Results about the Adjusted Winner Procedure
[Intended for a more general audience. Initial draft: comment welcome]Adjusted Winner ProcedureThe Adjusted Winner procedure is a well-known fair division mechanism to settle disputes and divide resource between two parties. It was proposed by political scientist Steven Brams and mathematician Alan Taylor:Since the allocation of resources is typically seen in the context of conflict and cooperation, the parties are referred to as agents  or player as is standard in the field of game […]
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6:12 PM | RIP John Nash
http://www.abelprisen.no/artikkel/vis.html?tid=63683
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3:04 PM | John Forbes Nash, Jr.: 1928-2015
Sad news. John Nash and his wife Alicia died in a car crash in New Jersey today. They were on their way back from Norway where Nash had received the Abel Prize. In game theory, Nash is best known for the concept of Nash equilibrium, for which he received the Nobel Prize in Economics in 1994. […]
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2:40 PM | Animated Logical Graphs : 9
Re: Ken Regan • The Shapes of Computations The insight that it takes to find a succinct axiom set for a theoretical domain falls under the heading of abductive or retroductive reasoning, a knack as yet refractory to computational attack, … Continue reading →
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8:44 AM | Asynchronous and decentralized teleportation of Turing Machines
The idea is that it is possible to copy a computer which executes a program, during execution, and to produce working clones. All this without any control (hence decentralized) and any synchronization. More than that, the multiple copies are done in the same time as the computers compute. I think is crazy, there’s nothing like … Continue reading Asynchronous and decentralized teleportation of Turing Machines →

May 23, 2015

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3:00 PM | Animated Logical Graphs : 8
Re: Ken Regan • The Shapes of Computations The most striking example of a “Primitive Insight Proof” (PIP❢) known to me is the Dawes–Utting proof of the Double Negation Theorem from the CSP–GSB axioms for propositional logic. There is a … Continue reading →
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10:15 AM | No Hesitations is Not a Phishing Site!
Google's "automatic system" a few days ago "determined" that No Hesitations  (fxdiebold.blogspot.com) was a phishing site. (Phishing sites attempt to scam users into revealing credit card numbers, etc. No Hesitations obviously can't be a phishing site, as users are never asked for any information of any kind.) So they shut it down, with only a terse and uninformative machine-generated "no-reply" email to me. Literally, No Hesitations just vanished! I then found a way to request a human […]
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9:15 AM | Unsurprising findings: universities damaged by “student as consumer” ideology
Academics under pressure to bump up student grades, Guardian survey shows “Many academics said recent reforms, which encourage universities to treat students as consumers and expand their intake, have damaged the quality of education offered to undergraduates. […]52% of academics said the emphasis placed on “the student experience agenda” had damaged the quality of education […]
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2:34 AM | Network Theory in Turin
Here are the slides of the talk I’m giving on Monday to kick off the Categorical Foundations of Network Theory workshop in Turin: • Network theory. This is a long talk, starting with the reasons I care about this subject, and working into details of one particular project: networks in electrical engineering and control theory. […]

May 22, 2015

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6:44 PM | Growth Rates VI
$\newcommand{\PG}{\text{PG}}$ Denser than a Geometry Hello everyone. In my last post, I discussed an unavoidable minor theorem for large matroids of density greater than $\binom{n+1}{2}$, which as a consequence characterised exactly the minor-closed classes of matroids that grow like the the graphic … Continue reading →
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3:22 PM | Animated Logical Graphs : 7
Re: Ken Regan • The Shapes of Computations There are several issues of computation shape and proof style that raise their heads already at the ground level of boolean functions and propositional calculus. The dimensions I have found most prominent … Continue reading →
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11:02 AM | Groups and Group Actions: Lecture 16
In which we meet Cayley’s Theorem and reach the end of this particular adventure, but catch a glimpse of far-off lands still to be explored. Theorem 68: Let be a group, let be a set. Given a left action of on , there is an associated homomorphism . Given a homomorphism , there is an associated […]

May 21, 2015

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11:58 PM | An Intentional and an Unintentional teaching experiment regarding proving the number of primes is infinite.
I taught Discrete Math Honors this semester. Two of the days were cancelled entirely because of snow (the entire school was closed) and four more I couldn't make because of health issues (I'm fine now). People DID sub for me those two and DID do what I would have done. I covered some crypto which I had not done in the past. Because of all of this I ended up not covering the proof that the primes were infinite until the last week. INTENTIONAL EXPERIMENT: Rather than phrase it as a proof by […]
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5:53 PM | On generalizations of separating and splitting families
With Daniel Condon, Luke Serafin, and Cody Stockdale. (arχiv) The work in this article is concerned with two different types of families of finite sets: separating families and splitting families (they are also called “systems”). These families have applications in combinatorial search, coding theory, cryptography, and related fields. We define and study generalizations of these two notions, which we have named $n$-separating families and $n$-splitting families. For each of […]
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5:26 PM | Information and Entropy in Biological Systems (Part 4)
I kicked off the workshop on Information and Entropy in Biological Systems with a broad overview of the many ways information theory and entropy get used in biology: • John Baez, Information and entropy in biological systems. Abstract. Information and entropy are being used in biology in many different ways: for example, to study biological […]
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3:32 PM | Morning Madness: An Ode to Mercedes S
This is the morning madness, of a drive along skyline.Cutting through fog as thick as stew and waves of dew,#@70mph, hugging the memorized curves without tapping the breaks,the top and windows down, listening to the tires searing and splattering the film of water,Mountains and cliffs shrouded in clouds in the clasp of prehistoric moments.At last, I reached the mission, the valley in SF, parked the car and let it sigh.
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3:12 PM | New preprint: Hölder continuity of solutions to quasilinear hypoelliptic equations (w/ C. Imbert)
DOWNLOAD THE PDF FROM ARXIV We prove that  weak solutions to a quasilinear hypoelliptic equations with bounded measurable coefficients are Hölder continuous. The proof relies on classical techniques developed by De Giorgi and Moser together with the averaging lemma developped in kinetic theory. The latter tool is used in the proof of the local gain […]
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12:54 PM | Alan Turing's declassified papers
@ulaulaman via @MathisintheAir about #AlanTuring on #arXiv Recently Ian Taylor has uploaded on arXiv a couple of declassified papers by Alan Turing about statistics, probability and cryptography: 1. The Statistics of RepetitionsIn order to be able to obtain reliable estimates of the value of given repeats we need to have information about repetition in plain language. Suppose for example that we have placed two messages together and that we find repetitions consisting of a tetragramme, two […]
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12:31 PM | Numerical Methods That (Usually) Work
A book that inspired me early in my career is Numerical Methods That Work by Forman S. Acton, published in 1970 by Harper and Row. Acton, a professor in the electrical engineering department at Princeton University, had a deep understanding … Continue reading →

May 20, 2015

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9:52 PM | Battle of the Students
The Game Theory course that I am teaching is accompanied by weekly exercises which include a so-called G-exercise. G-exercises are games that the students play with or against each other. The (expected) payoff they receive will be accumulated and counts towards their final course grade. Starting with the Prisoner’s Dilemma, these exercises include classics like […]
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9:44 PM | Bond Yields, Macro Fundamentals, and Policy
Greetings my friends from Eurovision in Vienna. Yes, OK, that's not exactly the real reason I'm here, but still...As I said in an earlier post that stressed DNS/AFNS yield-curve modeling with the zero lower bound imposed, "although Nelson-Siegel is almost thirty years old, and DNS/AFNS is almost a teenager, interesting and useful new variations keep coming." Another intriguing DNS/AFNS literature strand concerns the interaction of bond yields and macro fundamentals. That's […]
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7:58 PM | Information and Entropy in Biological Systems (Part 3)
We had a great workshop on information and entropy in biological systems, and now you can see what it was like. I think I’ll post these talks one a time, or maybe a few at a time, because they’d be overwhelming taken all at once. So, let’s dive into Chris Lee’s exciting ideas about organisms […]
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6:42 PM | MAS3111/8111 – Good luck tomorrow
Tomorrow my students at Newcastle have their MAS3111/8111 – PDEs exam. To those on the course, best of luck!
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3:22 PM | Il mito della pianta e del microonde
Quando leggo un titolo come "L'acqua scaldata al microonde uccide le piante" (c'è anche un vecchio articolo in inglese), inevitabilmente sento puzza di bruciato. E così vado a controllare.Effettivamente l'esperimento citato nell'articolo di cui sopra sembra stia stato fatto da tale Arielle Reynolds nel 2006 (vedi versione con più foto su archive.org) quando, studente delle superiori, prepara un progetto di scienze. Innaffia due piantine, una con acqua purificata e l'altra con acqua […]
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