Monthly Archives: January 2015

H_2(Gamma_N(p),Z)

Posted on January 30, 2015 by Persiflage

In this post (which is a follow-up to the last post), I wanted to compute the group \( H_2(\Gamma_N(p),\mathbf{Z})\), where \( \Gamma_N(p)\) is the congruence subgroup of \( \mathrm{SL}_N(\mathbf{Z})\) for large enough \( N\) and \( p\) is prime. In … Continue reading →

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Stable completed homology without Quillen-Lichtenbaum

Posted on January 21, 2015 by Persiflage

Having just made (hopefully) the final revisions on my paper on stable completed cohomology groups, I wanted to record here a few remarks which didn’t otherwise make it into the paper. The first is that, in addition to the result … Continue reading →

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Inverse Galois Problems II

Posted on January 13, 2015 by Persiflage

David Zywina was in town today to talk about a follow up to his previous results mentioned previously on this blog. This time, he talked about his construction of Galois groups which were simple of orthogonal type, in particular, the … Continue reading →

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Abelian Spiders

Posted on January 11, 2015 by Persiflage

This is a blog post about the thesis of my student Zoey Guo, who is graduating this year. (For a blog post on the thesis of my other student graduating this year, see this.) Let \(\Phi\) be a finite graph. … Continue reading →

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Higher direct images of canonical extensions

Posted on January 4, 2015 by Persiflage

I like Kai-Wen’s talks; he gives lots of examples, writes big with big chalk, and clearly explains the key points of the argument. I’m not sure I would classify his thesis as light reading material, but if he produced a … Continue reading →

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