%A ?. ?. Pogoru? %A Ram?n ?. Rodr?guez-Dagn?no %J Theor. Probability and Math. Statist. %T Asymptotic expansion for transport processes in semi-Markov media %X In this paper we study asymptotic expansions for a solution of the singularly perturbed equation for a functional of a semi-Markov random evolution on the line. By using the method for solutions of singularly perturbed equations, we obtain the solution in the form of a series of regular and singular terms. The first regular term satisfies a diffusion-type equation, and the first singular term is a semigroup with the infinitesimal operator of the respective related bivariate process. Each regular and singular term can be calculated recursively. %N 83 %D 2010 %L zu213404