Recent posts

May 3, 2020
The political economy of platforms
A platform for hamburgers. Think GrubHub. In this note, we’ll try to understand what is a platform, and whether they can be improved with a “coop” structure.…
May 25, 2016
Dubious Arguments
There’s a famous dubious argument that “proves” the set of $\mathrm{Tree}$ of (planar, rooted) binary trees is in bijection with the set of $7$-tuples of trees $\mathrm{Tree}^6$.…
Jan 18, 2016
One reason why the interaction between addition and multiplication is the interesting part of number theory
I’ve often heard people say that the interesting part of number theory is the interaction between addition and multiplication, but I only yesterday realized one reason why that is, triggered by convincing myself that $a b = \mathrm{lcm}(a,b)\mathrm{gcd}(a,b)$ (a train of thought triggered by seeing the letters “GCD” graffitied on a wall in Chicago).…
Jul 9, 2014
Infinite Games in Hyperbolic Groups
The other day I was sitting in The Coop in Cambridge, reading a book on combinatorial games, and so naturally I started wondering about games played in groups, or on their Cayley graphs at least.…
Jan 21, 2013
2001 Frames: Markov model movie
If I say the word “swimming” to you, you’ve got a fair bit of information about what word I’m going to say next.…