Category Archives: Uncategorized

Algebraic properties of chromatic polynomials, 2

My paper with Kerri Morgan on algebraic properties of chromatic roots (described here) has just appeared in the Electronic Journal of Combinatorics: you can find it here. I won’t say any more about it, except to pose a challenge which … Continue reading

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To my friends in the United States of America: I am sorry, but I do not expect I will be visiting you during the term of office of the current President. This for two reasons. First, I find his policies … Continue reading

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The days of our years are threescore years and ten; and if by reason of strength they be fourscore years, yet is their strength labour and sorrow; for it is soon cut off, and we fly away. So today I … Continue reading

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Impact update

My comments on impact were cited by Ursula Martin and her co-author Laura Meagher here. Worth a look. PS Here’s the abstract: This empirical study explored how research can generate impacts by investigating different sorts of impacts from one academic … Continue reading

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Automorphism groups of transformation semigroups

I have been in the transformation semigroups game for nearly ten years now, but I still feel that I am finding my feet. Here is apparently a huge difference between permutation groups and transformation semigroups, one which is still not … Continue reading

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Update on Babai’s result

I learned yesterday that Harald Helfgott had found a mistake in László Babai’s result on the complexity of graph isomorphism. The algorithm and the bulk of the analysis still stands; it was just problem with the accounting showing that the … Continue reading

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Happy New Year

Happy New Year! But where are we headed? As time goes on, fewer and fewer people actually visit this page, as opposed to subscribing by email or to the RSS feed, so the WordPress end-of-year report gives less information about … Continue reading

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