There are 10^11 stars in the galaxy. That used to be a huge number. But it's only a hundred billion. It's less than the national deficit! We used to call them astronomical numbers. Now we should call them economical numbers.
by Richard Feynman (1918 - 1988)

Convexity of torus-focus integrable systems

The following pdf file contains the slides of my talk on the convexity of integrable Hamiltonian systems with focus-focus singularities at the “Workshop on Integrable Systems and Applications”, IBS-CGP, Postech, 02 May 2018.