The "good'' Boussinesq equation: long-time asymptotics

We consider the initial-value problem for the ``good’’ Boussinesq equation on the line. Using inverse scattering techniques, the solution can be expressed in terms of the solution of a $3\times 3$-matrix Riemann-Hilbert problem. We establish formulas for the long-time asymptotics of the solution by performing a Deift-Zhou steepest descent analysis of a regularized version of this Riemann-Hilbert problem.