Author Archives: Persiflage

Office Toys

Posted on March 22, 2013 by Persiflage

I think I need one of these for my office, possibly to point at undergraduates when they ask for a higher grade: . For the full story, see here.

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Straight from the top to the bottom

Posted on March 4, 2013 by Persiflage

Possibly the worst programme on radio is NPR’s “from the top.” Ostensibly the show is about showcasing young performers in classical music. Yet, in reality, it is all about the incredibly annoying host, Christopher O’Riley, for whom condescension has become … Continue reading →

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Stephen Fry

Posted on February 14, 2013 by Persiflage

Never let it be said that this blog shies away from confronting sacred cows. Today’s target: Stephen Fry. In the video below, Fry tries to have his cake and eat it too — calling out grammar pedants for “showing off … Continue reading →

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Torsion in the cohomology of co-compact arithmetic lattices

Posted on February 6, 2013 by Persiflage

Various authors (including Bergeron and Venkatesh) have shown that the cohomology of certain arithmetic groups have a lot of torsion. For example, if \(\Gamma\) is a co-compact arithmetic lattice in \(\mathrm{SL}_2(\mathbf{C})\), and \(\mathcal{L}\) is an acyclic local system, then \(\log … Continue reading →

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A scandal in Romania

Posted on January 28, 2013 by Persiflage

I was invited to review some research proposals for the CNCS. They offered a modest remuneration for my time (something like €168, I believe). For privacy reasons I won’t comment on the proposals I read, suffice to say that they … Continue reading →

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Small Cyclotomic Integers

Posted on January 26, 2013 by Persiflage

Julia Robinson is a famous mathematician responsible for fundamental work in logic and in particular on Hilbert’s Tenth problem. Less well known nowadays is that her husband, Raphael Robinson, was a number theorist at Berkeley. One question R.Robinson asked concerned … Continue reading →

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Random p-adic Matrices

Posted on January 23, 2013 by Persiflage

Does anyone know if the problem of random matrices over (say) \(\mathbf{Z}_p\) have been studied? Here I mean something quite specific. One could do the following, namely, since \(\mathbf{Z}_p\) is compact with a natural measure, look at random elements in … Continue reading →

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NT Seminar: A haruspicy

Posted on January 18, 2013 by Persiflage

Following JSE’s advice, I will blog on something that I know absolutely nothing about. Apologies in advance for mathematical errors! SLM gave a number theory seminar this week about the first Betti number of \(\Gamma(n)\) — as \(n\) varies — … Continue reading →

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Number theory and 3-manifolds

Posted on January 13, 2013 by Persiflage

It used to be the case that the Langlands programme could be used to say something interesting about arithmetic 3-manifolds qua hyperbolic manifolds. Now, after the work of Agol, Wise, and others has blown the subject to smithereens, this gravy … Continue reading →

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Where even the flat tax is a liberal dream

Posted on January 3, 2013 by Persiflage

As Democrats and Republicans squabble over the expiration of the Bush tax cuts, it’s worth noting that at least in one corner of America, even the flat tax is considered too progressive. It used to be the case that if … Continue reading →

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