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# Posts

### May 27, 2015

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Organized by Université de Montpellier and LIRMM-CNRS with the support of the ANR project Polymnie, June 10-12 will see a really neat workshop on the use of epsilons and choice functions.  The program is now online; if you can, you should go. This workshop aims at promoting work on Hilbert’s Epsilon in a number of…

### May 26, 2015

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5/26/2015This page intentionally left blank.I'm sorry, but Spock would say "That's not logical." David
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6/11/2015 The Undecanacci Sequence: a(0) = a(1) = a(2) = a(3) = a(4) = a(5) = a(6) […]
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11/13/2015Today is "Friday the Thirteenth" - again.  This is the third one this year!!The next 5 years worth of "Friday the Thirtheenth"s are: […]

### May 25, 2015

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OEIS has a listing for Cyclops Prime - prime numbers that have one zero right in the middle, but nowhere else in the prime.  The one zero represents a Cyclops' one eye.  And they also note that the prime must have an odd number of digits, otherwise the one zero can't be "right in the middle"But I noticed that they left out a listing for those of us with two eyes.  So I have been searching for Binocular Primes, to represent those of us with two eyes. […]

### May 24, 2015

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5/25/2015The purpose of this sentence is to explain the purpose of this sentence.David
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5/24/2015 John Nash and his wife, Alicia, died today in an automobile accident. […]

### May 23, 2015

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"NERDY numbers", "Mr. B's Super-Duper-Fantastic, Magically Mystical and Wonderfully Mathematical Sequences Numbers" or Simply "Sequence Numbers" As I have mentioned, I have been working on a class of numbers that have the following properties: (1) they are integers, and (2) when they are raised to the -1 power (reciprocal, inverse, or written as a fraction with a one in the numerator, and the number in the denominator) they produce a decimal expansion that shows a recognizable sequence of […]

### May 22, 2015

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5/22/2015"This statement is false."David
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5/22/2015Mathematicians born on this day:1848 : Hermann Schubert1865 : Alfred Dixo […]
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5/22/2015"This statement is false."Is the statement shown above true or false?If it's true, well it says that it is false.If it's false, well it must be true.I think even Spock would find this "very illogical". David

### May 21, 2015

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(Continues part 1, part 2, and part 3; fork the full text on GitHub) Branches Programmers are fond of using “branches” in their code. A code branch is a version of the entire project that shares it change history, but includes some changes the main branch (usually called “master”) does not (yet) contain. This is…
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Anthony Millevolte is professor for chemistry at the University of Wisconsin Colleges where he also teaches the history of science courses. When he was teaching an introductory course on the so-called Copernican or Astronomical Revolution he realised that there was … Continue reading →
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5/21/2015:You may remember that my daughter (Peggy Sue - though most people just call her "Doctor") is a big fan of the number 13.  So I have prepared a new NERDY number for her.The new sequence is called the "Pegganacci Sequence".  It starts off like a Tridecanacci Sequence but each new term is the sum of the the prevous 13 terms, each multiplied by one of the numbers from 1 to 13.  Mathematicians would explain it this way: […]

### May 20, 2015

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You are familiar with river crossing problems I'm sure.  You know: A man has to cross a river with a wolf, a goat and a cabbage.  He has access to a small row boat, but he only has room for himself and one other item (either the wolf, the goat or the cabbage).  But he must not leave the wolf and the goat alone together on one side of the river or the wolf will eat the goat.  He also cannot leave the goat alone with the cabbage, because the goat will eat the cabbage.A student […]

### May 19, 2015

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(Continues part 1 and part 2; fork the full text on GitHub) Forks and Pull Requests If you have push access to a repository, you can sync your local clone with the remte on GitHub or GitLab directly. But many projects do allow push access only to a select group of people to make sure…
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As part of the 650-year celebration of the University of Vienna, the Institute Vienna Circle is putting on an exhibition on the Vienna Circle. The exhibition opens tomorrow. A central part of our exhibition will be devoted to the history of the racist and political persecution of intellectuals and scholars, leading to the exodus of…
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I will be hosting the 123rd Carnival of Mathematics in June 2015.  I you […]
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5/19/2015I really like the Online Encyclopedia of Integer Sequences.  I have […]

### May 18, 2015

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May 18th, 2015Mathematicians born on this day:1048 : Omar Khayyam1711 : Ruggero Bo […]

### May 17, 2015

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Non posso negare di aver gioito quando la professoressa Giovanna Arcadu mi ha fatto sapere dell'interesse suscitato dalla lettura del mio La Musica dei Numeri tra i suoi alunni della II media e di quanto il librino fosse stato utile per la spiegazione e la dimostrazione del Teorema di Pitagora."Tadaaa ... :-) Attentissimi, interessati, han colto perfino un refuso che a me era sfuggito", mi ha scritto la professoressa Arcadu su facebook. E, dopo essermi detto lusingato, sono subito partito alla […]

### May 16, 2015

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The Tribonacci Sequence is similar to the Fibonacci sequence, except we […]

### May 15, 2015

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Quite a stir has been caused in the Internet by an article written by David Abulafia and published in History Today entitled Britain: apart from or a part of Europe, which to put it quite simply argues for a British … Continue reading →
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Continues Git for Philosophers (pt. 1) Collaborative Writing with Git Collaborative writing presents similar issues as collaborative programming: different people making changes to the same document from different locations. Sending the document back and forth is inefficient: only one person can work on it at a time, and there is a risk of changes being…
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OK – I’m still having technical problems – let me try something different. […]

### May 14, 2015

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Stavolta è .mau. a ospitare l'edizione di maggio del Carnevale della Matematica.Io ho contribuito con la Cellula Melodica e con il mio articoletto così introdotto:Iniziamo subito con Dioniso! Anzi no, abbiamo davvero iniziato con lui perché la cellula melodica che vedete in alto è opera sua. Ma per chi non ama la musica e preferisce la buona tavola, su Pitagora e dintorni Dioniso ci presenta un Dialogo su una bottiglia di Klein. Cito: «…E così è nata l’idea […]
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In the most recent issue of the Bulletin, J. J. Green, Marcus Rossberg and Philip Ebert discuss the typography of Frege’s Grundgesetze. J. J. Green, Marcus Rossberg and Philip A. Ebert, “The Convenience of the Typesetter; Notation and Typography in Frege’s Grundgesetze der Arithmetik”, Bulletin of Symbolic Logic, vol. 21, no. 1, 15–30, Mar. 2015.…
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More on NERDY Numbers:I took some heat about using the word "NERDY".  I am a […]

### May 13, 2015

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A li’l paper I wrote in response to a question/conversation with Allen Hazen and Jeff Pelletier a couple of months ago went online today in the Journal  Philosophical Logic: Natural Deduction for the Sheffer Stroke and Peirce’s Arrow (and any Other Truth-Functional Connective) (If you’re not blessed with a Springer Link subscription, there’s a preprint…
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Would you like to spend a semester or two in beautiful Calgary, Canada, during the 2016/17 academic year? The University of Calgary is pleased to offer the opportunity for a Fulbright Visiting Research Chair in Logic or the Philosophy of Science. The visiting researcher will be a part of the Department of Philosophy and collaborate…