@unpublished{KellerRoellyValleriani2012,
  author    = {Keller, Peter and Roelly, Sylvie and Valleriani, Angelo},
  title     = {On time duality for quasi-birth-and-death processes},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-56973},
  year      = {2012},
  abstract  = {We say that (weak/strong) time duality holds for continuous time quasi-birth-and-death-processes if, starting from a fixed level, the first hitting time of the next upper level and the first hitting time of the next lower level have the same distribution. We present here a criterion for time duality in the case where transitions from one level to another have to pass through a given single state, the so-called bottleneck property. We also prove that a weaker form of reversibility called balanced under permutation is sufficient for the time duality to hold. We then discuss the general case.},
  language  = {en}
}