@inproceedings{4500,
  abstract     = {We investigate the expressive power of timing restrictions on labeled transition systems. In particular, we show how constraints on clock variables together with a uniform liveness condition—the divergence of time—can express Büchi, Muller, Streett, Rabin, and weak and strong fairness conditions on a given labeled transition system. We then consider the effect, on both timed and time-abstract expressiveness, of varying the following parameters: time domain (discrete or dense), number of clocks, number of states, and size of constants used in timing restrictions.},
  author       = {Henzinger, Thomas A and Kopke, Peter and Wong Toi, Howard},
  booktitle    = {22nd International Colloquium on Automata, Languages and Programming },
  isbn         = {9783540600848},
  location     = {Szeged, Hungary},
  pages        = {417 -- 428},
  publisher    = {Springer},
  title        = {{The expressive power of clocks}},
  doi          = {10.1007/3-540-60084-1_93},
  volume       = {944},
  year         = {1995},
}

@inproceedings{4518,
  abstract     = {The analysis, verification, and control of hybrid automata with finite bisimulations can be reduced to finite-state problems. We advocate a time-abstract, phase-based methodology for checking if a given hybrid automaton has a finite bisimulation. First, we factor the automaton into two components, a boolean automaton with a discrete dynamics on the finite state space B m and a euclidean automaton with a continuous dynamics on the infinite state space  n . Second, we investigate the phase portrait of the euclidean component. In this fashion, we obtain new decidability results for hybrid systems as well as new, uniform proofs of known decidability results.},
  author       = {Henzinger, Thomas A},
  booktitle    = {22nd International Colloquium on Automata, Languages and Programming },
  isbn         = {9783540600848},
  location     = {Szeged, Hungary},
  pages        = {324 -- 335},
  publisher    = {Springer},
  title        = {{Hybrid automata with finite bisimulations}},
  doi          = {10.1007/3-540-60084-1_85},
  volume       = {944},
  year         = {1995},
}