Hölder regularity of the Boltzmann equation past an obstacle

Abstract

Regularity and singularity of the solutions according to the shape of domains is a challenging research theme in the Boltzmann theory (\cite{Kim11,GKTT1}). In this paper, we prove an Hölder regularity in $C_{x,v}^{0,\frac{1}{2}-}$ for the Boltzmann equation of the hard-sphere molecule, which undergoes the elastic reflection in the intermolecular collision and the contact with the boundary of a convex obstacle. In particular, this Hölder regularity result is a stark contrast to the case of other physical boundary conditions (such as the diffuse reflection boundary condition and in-flow boundary condition), for which the solutions of the Boltzmann equation develop discontinuity in a codimension 1 subset (\cite{Kim11}), and therefore the best possible regularity is BV, which has been proved in \cite{GKTT2}.

49 pages, 2 figures, accepted in Comm. Pure Appl. Math

References in corpus (1)

• The large amplitude solution of the Boltzmann equation with soft potential