Decay of solutions of wave-type pseudo-differential equations over   p-adic fields
  During the eighties several physical models using p-adic numbers were proposed. Particularly various models of p-adic quantum mechanics. As a consequence of this fact several new mathematical problems emerged, among them, the study of p-adic pseudo-differential equations. In this paper we initiate the study of the decay of the solutions of wave-type pseudo-differential equations over p-adic fields; these equations were introduced by Kochubei in connection with the problem of characterizing the p-adic wave functions using pseudo-differential operators. We show that the solutions of p-adic wave-type equations have a decay similar to the solutions of classical generalized wave equations. 
W. A. Zuniga-Galindo