# Category Archives: Combinatorics

## Map of the world

At least as far as families of reflection groups with nice combinatorics are concerned

## “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

## “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  It is a collection of eight lectures delivered by the author in 1912 and 1913, and a fascinating historical document.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 , | 4 Comments

## Finding the magic coins

I’ve been reading through Daniel Velleman and Stan Wagon’s puzzle book Bicycle or Unicycle? and generally enjoying it – the puzzles include simple variations on classics, clever things I haven’t seen before, and some nontrivial uses of real mathematical thinking … Continue reading

Posted in Book reviews, Books, Combinatorics, Math | | 1 Comment

## 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

## 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.)

## 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 n-dimensional vector space over the finite field with … Continue reading