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Category Archives: Combinatorics
Map of the world
At least as far as families of reflection groups with nice combinatorics are concerned
Posted in Combinatorics, Math
Tagged permutations, complex reflection groups, reflection groups, Coxeter groups
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“Magical Mathematics” by Persi Diaconis and Ron Graham
This was a gift from my wonderful friend AHM, following the death of Graham last year. I enjoyed it quite a lot, but it’s also very weird. For example, chapters bounce around dramatically in tone and content (some are about … Continue reading
Posted in Book reviews, Books, Combinatorics, Math
Tagged de Bruijn sequence, Persi Diaconis, Ron Graham
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“Mathematical education” by G. St. L. Carson
This is the other book I mentioned finding at the Book Barn. It is a collection of eight lectures delivered by the author in 1912 and 1913, and a fascinating historical document. Some features that I found particularly interesting follow. … Continue reading
Posted in Book reviews, Books, Combinatorics, Education, Math
Tagged Formalism, Math education
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Jargon
This tickled my fancy: For all the other parameters, has no real structure. [R. Corran, E.K. Lee, S.J. Lee, Braid groups of imprimitive complex reflection groups, J. Algebra, 2015] (No, it’s not floppy — it’s a complex reflection group. Here … Continue reading
Posted in Combinatorics, Math
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Factor triples
Over at JD2718, Jonathan asks the following question: [A conference] presenter posed a problem that required finding three numbers that multiplied to make 72. The list included 1, 8, 9 and 2, 2, 18 and 3, 4, 6 and several … Continue reading
Open problems in algebraic combinatorics
This is pretty cool: Open Problems in Algebraic Combinatorics blog. (It’s attached to this conference.)
Posted in Academia, Combinatorics, Math
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Coincidences among small groups
I like to study reflection groups of various kinds. Let Sn denote the group of permutations of n points, let GL(n, q) denote the general linear group of invertible linear transformations of an ndimensional vector space over the finite field with … Continue reading
Posted in Combinatorics, Math
Tagged finite field, general linear group, group theory, permutations, symmetric group
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Herstmonceux
As I mentioned, after Vancouver I went to a conference at Herstmonceux Castle in Sussex, England. It was mathematically excellent, and I feel that BBC detective shows properly prepared me for my first visit to the UK. Trees in England … Continue reading
Posted in Academia, Combinatorics, Math, Trees
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The Erdős FBI file
A cute little article here about Paul Erdős’s FBI file. The short version is … that it’s not very interesting; the FBI routinely (and correctly) determined that he was just interested in doing mathematics. In a Minnesotacentric note, it was … Continue reading
Posted in Combinatorics, Math, What's the news?
Tagged combinatorics, congress, FBI, Math humor, Minnesota, Paul Erdos
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