Book #OTD
Graph Theory and Additive Combinatorics:
Exploring Structure and Randomness
book hp including PDF draft:
https://t.co/94SNckRq8W
publisher: https://t.co/iw1laSqVIQ
7 years ago the hardest problem P10 at IMC 2019 (university-level IMO) was this:
Take a triangle inside a circle. Prove that area of grey region is alwasy greater than area of the triangle.
Today GPT5.5 gave me a ridiculously elegant solution.