abstract: In his seminal works in Celestial Mechanics, H. Poincare emphasized the importance of homoclinicheteroclinic bifurcations as a source of rich dynamical phenomena.
A recent tour-de-force by J. Palis and J.-C. Yoccoz substantially advanced our understanding of heteroclinic bifurcations by showing that certain objects called "non-uniformly hyperbolic horseshoes" are very common near heteroclinic bifurcations of fat horseshoes.
In this talk, we will discuss some results (obtained in collaboration with J. Palis and J.-C. Yoccoz) about the fractal geometry of these "non-uniformly hyperbolic horseshoes".