Special Session 5: Recent developments in Partial Differential Equations from Physics

Regularity structure and asymptotic behavior of energy conservative solutions to the Hunter-Saxton equation
Tak Kwong Wong
The University of Hong Kong
Hong Kong
Co-Author(s):    Yu Gao and Hao Liu
Abstract:
The Hunter-Saxton equation is an integrable equation, and can be used to study the nonlinear instability in the director field of a nematic liquid. In this talk, we will first introduce a new generalized framework for energy conservative solutions of the Hunter-Saxton equation, and then discuss how to apply this new framework to investigate the regularity structure and long-time behavior of these solutions. In particular, some new observations have been found and rigorously shown: (i) singularities for the energy measure may only appear at at most countably many times, and are completely determined by the absolutely continuous part of initial energy measure; (ii) the temporal and spatial locations of singularities are explicitly determined by the initial data; and (iii) the long-time behavior of energy conservative solution is given by a kink-wave that is determined by the total energy of the system only.