Author Archives: Peter Cameron

About Peter Cameron

I count all the things that need to be counted.

Michael Atiyah

Posted on 12/01/2019

Sir Michael Atiyah died yesterday. I attended part of a course of lectures he gave on algebraic geometry in the 1970s (until term got too busy and I was forced to drop the course). They were excellent lectures, the sort … Continue reading →

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A family of non-synchronizing groups

Posted on 06/01/2019

As I explained recently, according to the O’Nan–Scott Theorem, a finite primitive permutation group either preserves a Cartesian structure, or is of affine, diagonal or almost simple type. In all these types except the last, the action of the group … Continue reading →

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Punctuation

Posted on 03/01/2019

Happy New Year everyone! A month ago I was engaged in a big fight with a major international academic publisher, whose typesetters had added commas to our paper in such a way as to change the meaning ssignificantly. Today I … Continue reading →

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Sophistry

Posted on 29/12/2018

The word “sophistry” means lies and deception, the kind of thing that more and more is associated with the pronouncements of politicians. I was prompted to think about this when the word came up in yesterday’s Guardian crossword, set by … Continue reading →

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The Hall–Paige conjecture

Posted on 18/12/2018

A Latin square of ordern is an n×n array of symbols from an alphabet of size n with the property that each symbol in the alphabet occurs once in each row or column. Two Latin squares L and M are … Continue reading →

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Normal

Posted on 14/11/2018

There are various overused terms in mathematics. “Normal” is one of them. Perhaps the four commonest uses are the following: A complex square matrix is normal if it commutes with its conjugate transpose. Normal matrices are precisely the ones which … Continue reading →

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Old Codger’s Combinatorics Conference

Posted on 09/11/2018

Wednesday was the Old Codger’s Combinatorics Conference at the University of Reading, a one-day meeting organised by Anthony Hilton. The position of the apostrophe is correct: it refers to the fact that Anthony admits that he is an old codger … Continue reading →

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