The Boltzmann-Grad limit and Cauchy-Kovalevskaya theorem

A technique based on the abstract Cauchy-Kovalevskaya theorem is used to de rive uniform estimates of solutions of BBGKY hierarchy, which improves Lanf ord's theorem on the Boltzmann-Grad limit and simplifies its proof, in part . It is also applied to the Euler limit of the Boltzmann hierarchy.