Category Archives: Mathematics

Abelian Varieties

Posted on October 30, 2013 by Persiflage

Jerry Wang gave a nice talk this week on his generalization of Manjul’s work on pointless hyperelliptic curves to hyperelliptic curves with no points over any field of odd degree (equivalently, \(\mathrm{Pic}^1\) is pointless). This work (link here) is joint … Continue reading →

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Who is D.H.J. Polymath?

Posted on October 20, 2013 by Persiflage

D.H.J. Polymath is the assumed collective pseudonym for the authors of a number of papers which have arisen as a result of the polymath project initated by Gowers. Presumably, since it is a matter of open record, one can go … Continue reading →

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Why is my paper taking so long to review?

Posted on October 1, 2013 by Persiflage

The question in the title does not refer to any of my own papers; rather, I want to *answer* the question from the perspective of an editor. Here, roughly, is how the sausage is made (this is a medium case … Continue reading →

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Virtual Congruence Betti Numbers

Posted on September 27, 2013 by Persiflage

Suppose that \(G\) is a real semisimple group and that \(X = \Gamma \backslash G/K\) is a compact arithmetic locally symmetric space. Let us call a cohomology class tautological if it is invariant under the group \(G\). For example, if … Continue reading →

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Life on the modular curve

Posted on September 24, 2013 by Persiflage

Alice and Bob live on the modular curve \(X_0(1) = \mathbf{H}/\mathrm{PSL}_2(\mathbb{Z})\). What does the world look like to them, assuming that they view the world in hyperbolic perspective? To those who are not used to hyperbolic geometry, there may be … Continue reading →

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En Passant III

Posted on August 31, 2013 by Persiflage

Question: When you are sick in bed, can you do any mathematics? I just spent the past few weeks with a sinus infection and was completely unable to do anything productive, that is, apart from writing an NSF grant (which … Continue reading →

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The Fundamental Curve of p-adic Hodge Theory, Part II

Posted on August 12, 2013 by Persiflage

This is a second post from JW, following on from Part I. The Galois group of \(\mathbb{Q}_p\) as a geometric fundamental group. In this follow-up post, I’d like to relay something Peter Scholze told me last fall. It concerns the … Continue reading →

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The Fundamental Curve of p-adic Hodge Theory, or How to Un-tilt a Tilted Field

Posted on July 23, 2013 by Persiflage

As Quomodocumque once said concerning the most recent set of courses at Arizona Winter School, “Jared Weinstein [gives] a great lecture.” On that note, I am delighted to welcome our first guest post, by the man himself. Note that it … Continue reading →

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Effective Motives

Posted on July 3, 2013 by Persiflage

This is a brief follow up concerning a question asked by Felipe. Suppose we assume the standard conjectures. Let \(M\) be a pure motive, and consider the following problems: Problem A: (“effectivity”) Suppose that \(M\) has non-negative Hodge-Tate weights. Then … Continue reading →

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Scholze on Torsion, Part IV

Posted on June 29, 2013 by Persiflage

This is a continuation of Part I, Part II, and Part III. I was planning to start talking about Chapter IV, instead, this will be a very soft introduction to a few lines on page 72. At this point, we … Continue reading →

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