Abstract
The μ-calculus is an expressive specification language in which modal logic is extended with fixpoint operators, subsuming many dynamic, temporal, and description logics. Formulas of μ-calculus are classified according to their alternation depth, which is the maximal length of a chain of nested alternating least and greatest fixpoint operators. Alternation depth is the major factor in the complexity of μ-calculus model-checking algorithms. A refined classification of μ-calculus formulas distinguishes between formulas in which the outermost fixpoint operator in the nested chain is a least fixpoint operator (Σ i formulas, where i is the alternation depth) and formulas where it is a greatest fixpoint operator (∏ i formulas). The alternation-free μ-calculus (AFMC) consists of μ-calculus formulas with no alternation between least and greatest fixpoint operators. Thus, AFMC is a natural closure of Σ 1 ∪ ∏ 1, which is contained in both Σ 2 and ∏ 2. In this work we show that Σ 2 ∩ ∏ 2 ≡ AFMC. In other words, if we can express a property ξ both as a least fixpoint nested inside a greatest fixpoint and as a greatest fixpoint nested inside a least fixpoint, then we can express ξ also with no alternation between greatest and least fixpoints. Our result refers to μ-calculus over arbitrary Kripke structures. A similar result, for directed μ-calculus formulas interpreted over trees with a fixed finite branching degree, follows from results by Arnold and Niwinski. Their proofs there cannot be easily extended to Kripke structures, and our extension involves symmetric nondeterministic Büchi tree automata, and new constructions for them.
Supported in part by by NSF grant CCR-9988172 and by a research grant from the Center for Pure and Applied Mathematics at the University of California, Berkeley
Supported in part by NSF grants CCR-9988322, CCR-0124077, IIS-9908435, IIS-9978135, and EIA-0086264, by BSF grant 9800096, and by a grant from the Intel Corporation.
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References
J.W. Addision, The theory of hierarchies. Proc. Internat. Congr. Logic, Method. and Philos. Sci. 1960, pages 26–37, Stanford University Press, 1962.
A. Arnold and D. Niwiński. Fixed point characterization of Büchi automata on infinite trees. Information Processing and Cybernetics, 8–9:451–459, 1990.
A. Arnold and D. Niwiński. Fixed point characterization of weak monadic logic definable sets of trees. In Tree Automata and Languages, pages 159–188, Elsevier, 1992.
A. Arnold and D. Niwiński. Rediments of μ-calculus. Elsevier, 2001.
A. Arnold and L. Santocanale, On ambiguous classes in the μ-calculus hierarchy of tree languages, Proc. Workshop on Fixed Points in Computer Science, Warsaw, Poland, 2003.
J. Benthem. Languages in actions: categories, lambdas and dynamic logic. Studies in Logic, 130, 1991.
J.C. Bradfield. The modal μ-calculus alternation hierarchy is strict. TCS, 195(2):133–153, March 1998.
R. Bloem, K. Ravi, and F. Somenzi. Efficient decision procedures for model checking of linear time logic properties. In Proc. 11th CAV, LNCS 1633, pages 222–235. 1999.
R. Cleaveland and B. Steffen. A linear-time model-checking algorithm for the alternation-free modal μ-calculus. In Proc. 3rd CAV, LNCS 575, pages 48–58, 1991.
E.A. Emerson and C.-L. Lei. Temporal model checking under generalized fairness constraints. In Proc. 18th Hawaii International Conference on System Sciences, 1985.
E.A. Emerson and C.-L. Lei. Efficient model checking in fragments of the propositional μ-calculus. In Proc. 1st LICS, pages 267–278, 1986.
M.J. Fischer and R.E. Ladner. Propositional dynamic logic of regular programs. Journal of Computer and Systems Sciences, 18:194–211, 1979.
M. Garey and D. S. Johnson. Computers and Intractability: A Guide to the Theory of NP-completeness. W. Freeman and Co., San Francisco, 1979.
M. Jurdzinski. Small progress measures for solving parity games. In 17th STACS, LNCS 1770, pages 290–301. 2000.
D. Janin and I. Walukiewicz. Automata for the modal μ-calculus and related results. In Proc. 20th MFCS, LNCS, pages 552–562. 1995.
R. Kaivola. On modal μ-calculus and Büchi tree automata. IPL, 54:17–22, 1995.
D. Kozen. Results on the propositional μ-calculus. TCS, 27:333–354, 1983.
D. Kozen and R. Parikh. A decision procedure for the propositional μ-calculus. In Logics of Programs, LNCS 164, pages 313–325, 1984.
O. Kupferman and M.Y. Vardi. Freedom, weakness, and determinism: from linear-time to branching-time. In Proc. 13th LICS, pages 81–92, June 1998.
O. Kupferman and M.Y. Vardi. The weakness of self-complementation. In Proc. 16th STACS, LNCS 1563, pages 455–466. 1999.
O. Kupferman and M.Y. Vardi. On clopen specifications. In Proc. 8th LPAR, LNCS 2250, pages 24–38. 2001.
O. Kupferman, M.Y. Vardi, and P. Wolper. An automata-theoretic approach to branching-time model checking. Journal of the ACM, 47(2):312–360, March 2000.
K.L. McMillan. Symbolic Model Checking. Kluwer Academic Publishers, 1993.
S. Miyano and T. Hayashi. Alternating finite automata on ω-words. TCS, 32:321–330, 1984.
A.W. Mostowski. Regular expressions for infinite trees and a standard form of automata. In Computation Theory, LNCS 208, pages 157–168. 1984.
D.E. Muller and P.E. Schupp. Alternating automata on infinite trees. TCS, 54:267–276, 1987.
D.E. Muller, A. Saoudi, and P.E. Schupp. Alternating automata, the weak monadic theory of the tree and its complexity. In Proc. 13th ICALP, LNCS 226, 1986.
D. Niwiński. On fixed point clones. In Proc. 13th ICALP, LNCS 226, pages 464–473. 1986.
M.O. Rabin. Weakly definable relations and special automata. In Proc. Symp. Math. Logic and Foundations of Set Theory, pages 1–23, 1970.
H. Rogers, Theory of recursive functions and effective computability. McGraw-Hill, 1967.
R.S. Street and E.A. Emerson. An elementary decision procedure for the μ-calculus. In Proc. 11th ICALP, LNCS 172, pages 465–472, 1984.
M. Takahashi. The greatest fixed-points and rational ω-tree languages. TCS 44, pp. 259–274, 1986.
M.Y. Vardi and P. Wolper. An automata-theoretic approach to automatic program verification. In Proc. 1st LICS, pages 332–344, 1986.
I. Walukiewicz. Private communication, 2003.
T. Wilke. CTL+ is exponentially more succinct than CTL. In Proc. 19th FST& TCS, LNCS 1738, pages 110–121, 1999.
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Kupferman, O., Vardi, M.Y. (2003). ∏2 ∩ Σ2 ≡ AFMC. In: Baeten, J.C.M., Lenstra, J.K., Parrow, J., Woeginger, G.J. (eds) Automata, Languages and Programming. ICALP 2003. Lecture Notes in Computer Science, vol 2719. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-45061-0_55
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