Perturbation approach to scaled type Markov renewal processes with infinite mean

Abstract: Scaled type Markov renewal processes generalize classical renewal processes: renewal times come from a one parameter family of probability laws and the sequence of the parameters is the trajectory of an ergodic Markov chain. Our primary interest here is the asymptotic distribution of the Markovian parameter at time t \to \infty. The limit, of course, depends on the stationary distribution of the Markov chain. The results, however, are essentially different depending on whether the expectations of the renewals are finite or infinite. If the expectations are uniformly bounded, then we can provide the limit in general (beyond the class of scaled type processes), where the expectations of the probability laws in question appear, too. If the means are infinite, then - by assuming that the renewal times are rescaled versions of a regularly varying probability law with exponent 0 \leq alpha \leq 1 - it is the exponent a which emerges in the limits.