TY - CHAP Y1 - 1990/// SN - 3-540-53048-7 N2 - This paper is concerned with bisimulation relations which do not only require related agents to simulate each others behavior in the direction of the arrows, but also to simulate each other when going back in history. First it is demonstrated that the back and forth variant of strong bisimulation leads to the same equivalence as the ordinary notion of strong bisimulation. Then it is shown that the back and forth variant of Milner's observation equivalence is different from (and finer than) observation equivalence. In fact we prove that it coincides with the branching bisimulation equivalence of Van Glabbeek & Weijland. Also the back and forth variants of branching, eegr and delay bisimulation lead to branching bisimulation equivalence. The notion of back and forth bisimulation moreover leads to characterizations of branching bisimulation in terms of abstraction homomorphisms and in terms of Hennessy-Milner logic with backward modalities. In our view these results support the claim that branching bisimulation is a natural and important notion. ED - C. M. Baeten, Jos ED - Willem Klop, Jan M1 - 458 A1 - De Nicola, Rocco A1 - Montanari, Ugo A1 - Vaandrager, Frits W. T2 - CONCUR '90 Theories of Concurrency: Unification and Extension SP - 152 T3 - Lecture Notes in Computer Science EP - 165 PB - Springer UR - http://dx.doi.org/10.1007/BFb0039058 TI - Back and Forth Bisimulations ID - eprints376 AV - none ER -