Wave speeds in the macroscopic relativistic extended model with many moments

An exact macroscopic extended model for relativistic gases, with an arbitrary number of moments, is present in the literature. It is determined except for a numberable family F of single variable functions whose physical meaning remains an open problem; a possibility is that it allows to apply the theory to a wider set of materials. Other models appearing in literature are particular cases of this macroscopic one when all these arbitrary functions are zero. Here we exploit equations determining wave speeds for that model. We find interesting results; for example, the whole system for their determination can be divided into independent subsystems which are expressed by linear combinations, through scalar coefficients, of tensors all of the same order. As expected, these wave speeds for the macroscopic model depend on F. Moreover, some wave speeds (but not all of them) are expressed by square roots of rational numbers.