I forgot to write the report last night as I got carried away with some mathematical discussions with a colleague; better late than never! First, I missed two talks today, due to forgetting the time mainly when I was talking with Simeon Ball about $(q+1)$-arcs of projective spaces. We’ve ended up doing something, and that’s what has occupied me in the last while. Anyway, Aart Blokhuis and Simeon Ball began their mini-course on “Polynomial methods in finite geometry” yesterday, beginning with blocking sets. What I took away was that Hasse derivatives do something that the standard derivatives do not, but I’m still at a bit of loss why they are so successful in capturing the information about directions determined by a function. After morning tea, Lev spoke on the state of the art on quadratic residues and difference sets. I found this harder to follow, but there were some very interesting tables on computer output where some strange things happen. Five primes come out as solutions on a test of trillions of integers. Luckily we will have the slides posted on the webpage so I can remember exactly what these computations were about. Then Stefaan De Winter gave a beautiful talk on partial difference sets, where he and his co-authors have knocked off most of Ma’s list of parameters on at most 100 vertices. This was very impressive. There’s more on this talk over at Peter Cameron’s blog.