Symplectic embeddings and continued fractions

As shown by Gromov's nonsqueezing theorem, symplectic embedding problems lie at the heart of symplectic topology. The four dimensional problem is rather different from that in higher dimensions. Recently it has become possible to specify exactly when a four dimensional ellipsoid embeds in a ball. The talk explains recent joint work with Schlenk on this question, exploring its unexpected connections to continued fractions, Fibonacci numbers and lattice packing problems.