October 02, 2014

8:08 AM | More logic, phil. maths, foundations blogs?
Inspired by Brian Weatherson’s new blogroll of “active philosophy blogs” with substantive content (where, sob, Logic Matters doesn’t get a mention — I must try harder, obviously), I thought it was more than time to update the blogroll here. So alongside … Continue reading →
5:47 AM | Mirror descent is, in a precise sense, a second order algorithm
For one of our projects at eBay, I’ve been attempting to do a Poisson MLE fit on a large enough dataset that Fisher scoring is not feasible. The problem is that the data also has such large variance in the scales of the observation that stochastic gradient descent does not work, period — because of […]
2:57 AM | Do optimal proof systems exist? (guest post by Olaf Beyersdorff)
This post is a survey on optimal proof systems. I will not cover any results in detail, but try to present the general picture of what is known and what to expect. A general proof system in the sense of Cook and Reckhow (1979) can be understood as a nondeterministic guess-and-verify algorithm. The question whether […]

October 01, 2014

9:55 PM | La tavola delle coniche
da Cyclopaedia, 1728
5:17 PM | Visual tutorial for “the soup”
I started here a visual tutorial for chemlambda and it’s gui in the making. I call it a tutorial for the “soup” because it is about a soup of molecules. A living soup. Hope that in  the  recent future will become THE SOUP. The distributed soup. The decentralized living soup. Bookmark the page because content […]
4:54 PM | Validity in Interpretation Chapter 4
We are back with the next set of notes on E.D. Hirsch, Jr.’s Validity in Interpretation. This chapter is on Understanding, Interpretation, and Criticism. I found it to be the least interesting as a whole. It mostly involved clarifying some … Continue reading →
4:06 PM | Technical Update: The Switch to MathJax
AZC has switched from WP-LaTeX to MathJax. There was no real problem with WP-LaTeX, but MathJax offered some improvements: Improved rendering Local installation: MathJax can be installed on your own webserver, so that you’re no longer reliant on external services Easier typing of LaTeX: in WP-LaTeX, you have to type the word LaTeX after the […]
2:36 PM | Oy Faye! What are the odds of not conflating simple conditional probability and likelihood with Bayesian success stories?
Congratulations to Faye Flam for finally getting her article published at the Science Times at the New York Times, “The odds, continually updated” after months of reworking and editing, interviewing and reinterviewing. I’m grateful too, that one remark from me remained. Seriously I am. A few comments: The Monty Hall example is simple probability not statistics, and finding that fisherman […]
1:30 PM | What’s The Use?
What’s the use of getting up in the morning? Never mind that now, I’m already up. Be constructive.  Try to focus on something positive. Okay, then, what’s the use of logic? You call that focused?  Be more specific! So what’s … Continue reading →
1:21 PM | From Nash equilibria to collective behavior
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 […]
6:28 AM | Reflections on Teaching
I was recently asked to be part of an advice panel for newly minted teaching assistants. Oh, how time flies! After assisting with numerous classes and teaching vector calculus twice, I’d like to think I have some advice to offer. … Continue reading →
4:58 AM | The “bounded gaps between primes” Polymath project – a retrospective
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 […]
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 Works of Wenzel […]
12:00 AM | Limits of prediction: stochasticity, chaos, and computation
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

8:46 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 al […]

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:

4:17 PM | Dagstuhl on Algebra in Computational Complexity
(Reminder- Theory day at UMCP: here is the link. ) There was a Dagstuhl on Algebra in Computational Complexity Sept 22-26. I learned stuff in the talks, over meals, and even in my room alone at night. 1) Recall that a while back Ryan Williams (the theorist, not the American-Football player) showed that NEXP is not in ACC. His proof involved MANY things but one of the core things was an ALGORITHM for a version of  SAT (I think Succinct-SAT) that was ever-so-slightly better than […]
3:51 PM | Sum of Squares: Upper bounds, lower bounds, and open questions
[Note: As I commented on Omer's touching post, I too was shocked by the sudden closure of the amazingly successful MSR Silicon Valley lab. I hope that this blog, whose contents had very little to do with MSR itself and everything to do with the great group of people that was there, would continue to […]
2:52 PM | Letter from George (Barnard)
Memory Lane: (2 yrs) Sept. 30, 2012. George Barnard sent me this note on hearing of my Lakatos Prize. He was to have been at my Lakatos dinner at the LSE (March 17, 1999)—winners are permitted to invite ~2-3 guests*—but he called me at the LSE at the last minute to say he was too ill to […]

September 29, 2014

9:06 PM | Everyday Sexism in STEM – A New Website
It is common knowledge that women are heavily under-represented in STEM disciplines (science, technology, engineering, and mathematics), despite efforts to recruit and retain more women in these fields. Though progress has been made, a recent paper from Yale University researchers … Continue reading →
3:45 PM | Imparare la matematica con le gif animate
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 ispirare un esercizio su GeoGebra, visto […]
1:39 PM | Statement by some academics at the University of Cambridge about Gaza
Lift the blockade on Gaza – End the killing – Justice for the Palestinians Cambridge academics speak out against occupation and violence Statement by academics at the University of Cambridge This statement comes from academics at the University of Cambridge, from a range of disciplines, and from a range of political, religious and cultural backgrounds. […]
1:00 PM | Frankl, My Dear : 4
Re: Dick Lipton & Ken Regan • (1) • (2) Let’s go back to the “key lemma” from (2) and try it out on a simple example, just to get a sense of what the terms mean. Lemma.  Let be … Continue reading →
11:24 AM | A Mind-Blowing Optimal Prediction Result
I concluded my previous post with:Consider, for example, the following folk theorem: "Under asymmetric loss, the optimal prediction is conditionally biased." The folk theorem is false. But how can that be?What's true is this: The conditional mean is the L-optimal forecast if and only if the loss function L is in the Bregman family, given by$$L(y, \hat{y}) = \phi (y) - \phi (\hat{y}) - \phi ' ( \hat{y}) (y - \hat{y}).$$ Quadratic loss is in the Bregman family, so the optimal prediction is […]
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 laboratory […]
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 avventure galanti, al […]
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, from just […]

September 28, 2014

8:43 PM | Pleasures of Being a Professor II: Hangouts
Professors are available to graduate students in different ways:  in dept coffee rooms, in their office behind open doors,  at weekly dept talks,  via email,  who knows, maybe some via their own apps!  I do a video hangout with CS graduate students of Rutgers every week. It lasts 1 hour and is open to all: not just my students -- they dont make it --- or theory or database students, but all students. I did this in Spring and am doing this again in Fall.  In Spring, […]
6:56 PM | Pleasures of Being a Professor I: Phd Students
Alex Nikolov defended his thesis related to discrepancy, and is now on his way to U. Toronto, after a brief stop at MSR, Redmond. Congratulations, Sasho!
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 at the […]
3:54 PM | Invisibility cloak unveiled!
Awful pun in the title, sorry! So here is the news. Scientists at Rochester have invented – well, not quite invented, but significantly improved over old versions – a device which works as an invisibility cloak. The new approach not only results in better concealment of the object, but can also use cheaper materials. In fact, […]
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