Tag Archives: groups


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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BCC, day 2

There was a London Mathematical Society regional meeting in the University of Warwick today, to be followed by a workshop on finite simple groups to celebrate the birthday of Richard Lyons, one of the pioneers and heroes of the Classification. … Continue reading

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OuLiPo, or Ouvroir de Littérature Potentielle (which they translate as “Charity bazaar of potential literature”) were a collection of writers I knew little about until yesterday. I knew a couple of things: Martin Gardner wrote about them, mentioning among other … Continue reading

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Entropy and groups

Yesterday I gave a talk on a theorem of Terence Chan, which he spoke about at a network coding meeting at Queen Mary in late 2012. He sketched a proof on the common room table after the talk, and I … Continue reading

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Lecture notes

I have decided to follow Dima’s suggestion and post my collection of lecture notes here. You will find them from the page “Lecture notes” on the menu bar at the bottom of the picture at the top of the blog. … Continue reading

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Transitivity and synchronization

Let Sn be the symmetric group of all permutations of {1,…,n}, and Tn the full transformation monoid of all functions from this set to itself. Recently I have come to the meta-conjecture that there is a fairly close analogy between … Continue reading

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Groups with unique involution

I discussed the binary polyhedral groups in the second post on the ADE diagrams. A more general class of groups has cropped up a couple of times recently, namely finite groups containing a unique involution. I’d like to discuss them … Continue reading

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