Logic of Programs 1985: Logics of Programs pp 413-424 | Cite as

The taming of converse: Reasoning about two-way computations

  • Moshe Y. Vardi
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 193)


We consider variants of propositional dynamic logic (PDL) augmented with the converse construct. Intuitively, the converse α of a program α is a programs whose semantics is to run α backwards. While PDL consists of assertions about weakest preconditions, the converse construct enable us to make assertions about strongest postconditions. We investigate the interaction of converse with two constructs that deal with infinite computations: loop and repeat. We show that converse - loop - PDL is decidable in exponential time, and converse - repeat - PDL is decidable in nondeterministic exponential time.


Execution Sequence Hybrid Automaton Tree Automaton Loop Formula Propositional Dynamic Logic 
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Copyright information

© Springer-Verlag Berlin Heidelberg 1985

Authors and Affiliations

  • Moshe Y. Vardi
    • 1
  1. 1.Center for Study of Languages and InformationStanford UniversityUSA

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