Fortnightly links (102)

These are trying times. I am not in a position to make any insightful comments. Just take care of your loved ones and yourself. I don't know to which extent reading math papers is high on one's wishlist now with more important matters to take care of. It's not high on mine in any case. So the first fortnightly link requires only a short attention span, whilst the others are more substantial.

• MathSciNet reviews by Richard Thomas are a gem of great insights and observations, with the occasional colourful comment. E.g. his review for Homological mirror symmetry for the 4-torus by Abouzaid–Smith contains the following piece of advice:

  So at this point the nonexpert should stop reading, appreciate the wonderful result and wait for the theory to settle down and simplify.

• János Kollár, Max Lieblich, Martin Olsson, Will Sawin: Topological reconstruction theorems for varieties elaborates on the reconstruction results for algebraic varieties using only the topological space. As Max himself tweeted:

  If you’re looking for a distraction, here's a math paper, joint with János Kollár, Martin Olsson, and Will Sawin. The main theorems struck us as pretty crazy. See if you can find a counterexample!

• Matt Booth: Singularity categories via the derived quotient has no spicy quote from the author to entice to read it (as far as I know), although the author is (at the time being likely only in theory) in the office neighbouring mine at the University of Antwerp (I haven't checked). Let me just point out that it gives a proof of the Donovan–Wemyss conjecture classifying threefold flopping contractions in terms of the (derived) contraction algebra.