Weak convergence of the integral of semi-Markov processes
Andrea Pedicone, Fabrizio Cinque
TL;DR
This work establishes functional weak convergence results for the integral of semi-Markov velocity processes, showing that, under mild moment and mixing conditions, the normalized integral $X_\lambda(t)=\lambda^{-1/2}(X(\lambda t)-\lambda\theta t)$ converges to a scaled Brownian motion $\mu^{-1/2}\gamma W$ in $C[0,\infty)$, where $\theta$ is the mean drift and $\gamma^2$ is determined by the stationary Markov renewal structure. The authors build a unified framework using regenerative and Markov renewal theory, proving ergodic, mixing, and renewal-type limit theorems for related functionals, and derive a precise expression for the limiting variance in terms of cycle sums and cross-correlations. They treat both the general semi-Markov case and the alternating renewal (periodic) specialization, addressing the challenges of non-ergodicity by delayed regenerative analysis and providing a consistent Brownian limit with explicit drift and diffusion parameters. As an application, they specialize to the generalized telegraph process, showing convergence to Brownian motion with drift and giving connections to the telegraph equation and its Kac-type diffusion limit to the heat equation. These results extend the weak-limit theory of telegraph-type motions and offer rigorous tools for analyzing finite-velocity particle models driven by semi-Markov dynamics.
Abstract
We study the asymptotic properties, in the weak sense, of regenerative processes and Markov renewal processes. For the latter, we derive both renewal-type results, also concerning the related counting process, and ergodic-type ones, including the so-called phi-mixing property. This theoretical framework permits us to study the weak limit of the integral of a semi-Markov process, which can be interpret as the position of a particle moving with finite velocities taken for a random time according to the Markov renewal process underlying the semi-Markov one. Under mild conditions, we obtain the weak convergence to scaled Brownian motion. As a particular case, this result establishes the weak convergence of the classical generalized telegraph process.
