Flat coalgebraic fixed point logics

  • Authors:
  • Lutz Schröder;Yde Venema

  • Affiliations:
  • DFKI Bremen and Department of Computer Science, Universität Bremen;ILLC, Universiteit van Amsterdam

  • Venue:
  • CONCUR'10 Proceedings of the 21st international conference on Concurrency theory
  • Year:
  • 2010

Quantified Score

Hi-index 0.03

Visualization

Abstract

Fixed point logics are widely used in computer science, in particular in artificial intelligence and concurrency. The most expressive logics of this type are the µ-calculus and its relatives. However, popular fixed point logics tend to trade expressivity for simplicity and readability, and in fact often live within the single variable fragment of the µ-calculus. The family of such flat fixed point logics includes, e.g., CTL, the *-nesting-free fragment of PDL, and the logic of common knowledge. Here, we extend this notion to the generic semantic framework of coalgebraic logic, thus covering a wide range of logics beyond the standard µ-calculus including, e.g., flat fragments of the graded µ-calculus and the alternating-time µ-calculus (such as ATL), as well as probabilistic and monotone fixed point logics. Our main results are completeness of the Kozen-Park axiomatization and a timed-out tableaux method that matches EXPTIME upper bounds inherited from the coalgebraic µ-calculus but avoids using automata.