Published online by Cambridge University Press: 14 July 2016
A necessary and sufficient condition of Serfozo (1971) for lumpability of semi-Markov processes is reinterpreted in terms of first-exit times. Furthermore, a new necessary and sufficient condition is developed by establishing relationships between first-passage times and lumpability of semi-Markov processes. The approach taken in this paper is entirely based on the Laplace-transform domain.
This paper has been partially supported by the IBM Program of Support for Education in the Management of Information Systems and by NSF Grant ECS-8600992.