Tag Archives: coherent configurations

Peter Neumann’s 3p paper

Posted on 15/04/2022 by Peter Cameron

In 1955, Helmut Wielandt published a paper proving the following theorem: Let G be a primitive permutation group of degree 2p, where p is a prime greater than 3, which is not doubly transitive. Then p = 2a2+2a+1 for some positive integer … Continue reading →

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G2D2, 2: first week

Posted on 18/08/2019 by Peter Cameron

The campus of the China Three Gorges Hotel has a small river, full of waterlilies and lotus flowers. Beside it runs a main road, along which big water trucks run, shooting atomised water from cannon-like structures; we are told this … Continue reading →

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Pilsen, days 1 and 2

Posted on 03/07/2018 by Peter Cameron

The conference on “Symmetry vs Regularity” in Pilsen has begun. I hesitate at trying to describe the talks, since the first day alone had 13 talks, and the second day 19, of lengths ranging from ten minutes to an hour, … Continue reading →

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Symmetry vs Regularity

Posted on 06/12/2017 by Peter Cameron

This is the title of a conference to be held next year (2018) from 1 to 7 July, in Pilsen, Bohemia, Czech Republic. The subtitle is “The first 50 years since Weisfeiler-Leman stabilization”, and the webpage is here. If you … Continue reading →

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Asymptotic group theory, 4

Posted on 21/08/2015 by Peter Cameron

Thursday was a national holiday in Hungary, St Stephen’s Day if you are religious or traditional, Constitution Day if you are a communist. “The shrewd communists let the parliament pass the new constitution on August 20, 1949,” in the words … Continue reading →

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Busy times, 8: Algebraic graph theory at Villanova

Posted on 08/06/2014 by Peter Cameron

This week, five time zones to the west; next week, three to the east. This week was Andrew Woldar’s conference on algebraic graph theory at Villanova University, a Catholic school founded by Irish Augustinian friars in about 1850. I had … Continue reading →

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Synchronizing coherent configurations

Posted on 23/08/2012 by Peter Cameron

In previous posts I have discussed coherent configurations and synchronization. Yesterday I realised that these two topics can be combined … Synchronization A (finite-state, deterministic) automaton consists of a finite set of states and a finite set of transitions, each … Continue reading →

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