Equation of state at ultrahigh densities and the speed of sound

We consider a system of baryons interacting through the exchange of massive neutral vector mesons at densities of rho > or = 1015 g/cm3, where they form a lattice. For densities 1016 > or = rho > or = 1015 g/cm3 we show that epsilon>3P and v/sub s/<1 even though the interaction energy dominates the kinetic energy. We discuss the practicality of this model and its implications for the neutron-star mass limit. We also consider its relation to the work of Zel'dovich and of Bludman and Ruderman