Today we had the last day of the information theory summer school and Rudiger Urbanke gave a lecture on LDPC codes, random graphs, polar codes and other ways to approach Shannon Capacity.

After it was over, I received a few emails about a potential proof that P is not equal to NP from Vinay Deolalikar.

A quick look at the proof seems (to my ignorant eyes) like a serious, well-written attempt, and some people who know more seem to agree.

Surprisingly, Replica symmetry breaking, random graphs (and how they are locally tree-like) and inference on graphical models (things we discussed in the school) seem to be central in the arguments.

Let’s hope the proof is correct!