2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/69480We consider the initial value problem for a pseudodifferential equation with first order hyperbolic part, and an order $γ> 0$ dissipative term. Under an assumption, depending on an integer parameter $L \geq 2$ such that $2 γ< L$, we construct for this initial value problem a parametrix that is a Fourier integral operator of type $ρ= 1 - γ/L$. The assumption implies that where the principal symbol of the dissipative term is zero, the terms of order up to $L-1$ in its Taylor series also vanish.19 pagesAnalysis of PDEs35S10text