“…Trying out techniques which work for nonlinear dispersive PDEs on the Boltzmann equation is not without precursors. For years, there have been many nice developments [1,2,4,5,42,43,45,58,60,66,68,70] which have hinted at or used space-time estimates like the Chermin-Lerner spaces or the harmonic analysis related to nonlinear dispersive PDEs, and many of them have reached global (strong and mild) solutions if the datum is close enough to the Maxwellians or satisifes some conditions. In the same period of time, the theory of nonlinear dispersive PDEs has matured into a stage on which the working function spaces have been cleanly unified, the well-posedness and ill-posedness (See, for example, the now well-known work [38, 39, 49-51, 56, 57] and also the survey [69] and the references within.)…”