TY - GEN
T1 - A Step Up in Expressiveness of Decidable Fixpoint Logics
AU - Benedikt, Michael
AU - Bourhis, Pierre
AU - Boom, Michael Vanden
N1 - Publisher Copyright:
© 2016 ACM.
PY - 2016/7/5
Y1 - 2016/7/5
N2 - Guardedness restrictions are one of the principal means to obtain decidable logics - - operators such as negation are restricted so that the free variables are contained in an atom. While guardedness has been applied fruitfully in the setting of first-order logic, the ability to add fixpoints while retaining decidability has been very limited. Here we show that one of the main restrictions imposed in the past can be lifted, getting a richer decidable logic by allowing fixpoints in which the parameters of the fixpoint can be unguarded. Using automata, we show that the resulting logics have a decidable satisfiability problem, and provide a fine study of the complexity of satisfiability. We show that similar methods apply to decide questions concerning the elimination of fixpoints within formulas of the logic.
AB - Guardedness restrictions are one of the principal means to obtain decidable logics - - operators such as negation are restricted so that the free variables are contained in an atom. While guardedness has been applied fruitfully in the setting of first-order logic, the ability to add fixpoints while retaining decidability has been very limited. Here we show that one of the main restrictions imposed in the past can be lifted, getting a richer decidable logic by allowing fixpoints in which the parameters of the fixpoint can be unguarded. Using automata, we show that the resulting logics have a decidable satisfiability problem, and provide a fine study of the complexity of satisfiability. We show that similar methods apply to decide questions concerning the elimination of fixpoints within formulas of the logic.
U2 - 10.1145/2933575.2933592
DO - 10.1145/2933575.2933592
M3 - Conference contribution
AN - SCOPUS:84994683519
T3 - Proceedings - Symposium on Logic in Computer Science
SP - 817
EP - 826
BT - Proceedings of the 31st Annual ACM-IEEE Symposium on Logic in Computer Science, LICS 2016
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 31st Annual ACM/IEEE Symposium on Logic in Computer Science, LICS 2016
Y2 - 5 July 2016 through 8 July 2016
ER -