Author Archives: Persiflage

Picard Groups of Moduli Stacks update

Posted on May 27, 2020 by Persiflage

A tiny update on this post. I was chatting with Benson and realized that I may as well ask him directly for a presentation of the mapping class group of a genus two surface. Perhaps unsurprisingly, it can be found … Continue reading →

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Panel Discussion: Mathematics Research Online

Posted on May 13, 2020 by Persiflage

Odds are high that virtual conferences in mathematics are here to stay. It seems crucial, therefore, to think long and hard about ways to make them work for all participants. We need to have conversations as a community to better … Continue reading →

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Picard Groups of Moduli Stacks

Posted on April 30, 2020 by Persiflage

Here are some algebraic geometry musings related to the last post, most of which is hopefully correct. Everything below is secretly over \(\mathbf{Z}[1/6]\) but I think one may as well think about what is happening over \(\mathbf{C}\). Warning: I don’t … Continue reading →

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Chidambaram on genus two curves, II

Posted on April 24, 2020 by Persiflage

We now continue a series of posts on the work of my student Shiva Chidambaram. (Click here for part I.) Today I would like to discuss another project with Shiva that was also joint with David Roberts (no, not David … Continue reading →

Posted in Mathematics, Students, Work of my students | Tagged , , , , , , , , , | 2 Comments

En Passant VIII

Posted on April 23, 2020 by Persiflage

I just found out that Lucien Szpiro recently passed away. I met him only once in late 2018 when I gave the joint NY number theory at CUNY. When I arrived at my hotel (the Gregory) around 10pm, I was … Continue reading →

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En Passant VII

Posted on April 19, 2020 by Persiflage

Idle question which has surely been asked (and answered!). If \(X^{+}_{\mathrm{nsp}}(p)\) is the modular curve corresponding to the normalizer of the non-split Cartan, then one reason it is hard to find all rational points is that the all factors of … Continue reading →

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Chidambaram on genus two curves, I

Posted on April 15, 2020 by Persiflage

Before we start, just to alert you to a minor blogpage design change: all the posts (including this one) which talk about my students work can be accessed in one place by clicking the “work of my students” tab just … Continue reading →

Posted in Mathematics, Students | Tagged , , , , , , , , , , , , | 8 Comments

How to reject a paper

Posted on March 31, 2020 by Persiflage

I just had the paper discussed in this post very quickly rejected. Since it was such a short paper, I thought it not too unreasonable to submit it to a strong journal, so I am not terribly disappointed. I can … Continue reading →

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You are welcome, Northwestern junior faculty

Posted on March 27, 2020 by Persiflage

Nobody has even accused Persiflage of being afraid to speak truth to power. After Chicago made their announcement that they were extending tenure by one year for all (qualified) faculty, I thought that, as a good local citizen of Evanston, … Continue reading →

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More on Lehmer’s Conjecture

Posted on March 21, 2020 by Persiflage

Lehmer said it was a “natural question” whether there existed an integer such that \(\tau(n)=0\) or not. I’ve wondered a little bit recently about how reasonable this is. (See this post.) The historical context is presumably related to the fact … Continue reading →

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