Hyperbolicity of exact hydrodynamics for three-dimensional linearized Grad's equations

We extend a recent proof of hyperbolicity of the exact (to all orders in Knudsen number) linear hydrodynamic equations [M. Colangeli et al, Phys. Rev. E (2007), in press; arXiv:cond-mat/0703791v2] to the three-dimensional Grad's moment system. A proof of an H-theorem is also presented.