Pushdown Automata
نویسنده
چکیده
Families of Languages AFL thm if F is closed under substitution with λ-free regular sets, morphism, union with regular sets [easy for cfg] & intersection with regular sets, then F is closed under inverse morphism Figure 26: closure properties of CF II 12 intersection with regular languages a;A/α a a;A/α λ;A/α λ;A/α { } } { ⇒ ⇒ { anbn | n ≥ 1 }∗ ∩ { w ∈ {a, b}∗ |#ax even } r1 p1 q1 r0 p0 q0 r p q λ λ;Z/Z a;+A b;A/λ λ;Z/Z λ λ;Z/Z b;A/λ λ λ;Z/Z b;A/λ λ;Z/Z λ;Z/Z a;+A a;+A 0
منابع مشابه
On Quantum Pushdown Automata
Quantum finite automata, as well as quantum pushdown automata were first introduced by C. Moore, J. P. Crutchfield [MC 97]. In this paper we introduce the notion of quantum pushdown automata in a non-equivalent way, including unitarity criteria, by using the definition of quantum finite automata of [KW 97]. It is established that the unitarity criteria of quantum pushdown automata are not equiv...
متن کاملReducing Deep Pushdown Automata
This contribution presents reducing variant of the deep pushdown automata. Deep pushdown automata is a new generalization of the classical pushdown automata. Basic idea of the modification consists of allowing these automata to access more deeper parts of pushdown and reducing strings to non-input symbols in the pushdown. It works similarly to bottom-up analysis simulation of context-free gramm...
متن کاملOn the Complexity of Bisimulation Problems for Pushdown Automata
All bisimulation problems for pushdown automata are at least PSPACE-hard. In particular, we show that (1) Weak bisimilarity of pushdown automata and nite automata is PSPACE-hard, even for a small xed nite automaton, (2) Strong bisimilarity of pushdown au-tomata and nite automata is PSPACE-hard, but polynomial for every xed nite automaton, (3) Regularity ((niteness) of pushdown automata w.r.t. w...
متن کاملOn the Expressive Power of 2-Stack Visibly Pushdown Automata
Visibly pushdown automata are input-driven pushdown automata that recognize some non-regular context-free languages while preserving the nice closure and decidability properties of finite automata. Visibly pushdown automata with multiple stacks have been considered recently by La Torre, Madhusudan, and Parlato, who exploit the concept of visibility further to obtain a rich pushdown-automata cla...
متن کاملA Logical Characterization for Dense-Time Visibly Pushdown Automata
Two of the most celebrated results that effectively exploit visual representation to give logical characterization and decidable modelchecking include visibly pushdown automata (VPA) by Alur and Madhusudan and event-clock automata (ECA) by Alur, Fix and Henzinger. VPA and ECA—by making the call-return edges visible and by making the clock-reset operation visible, respectively—recover decidabili...
متن کاملRamsey-Based Inclusion Checking for Dense-Stack Visibly Pushdown Automata
Visibly pushdown automata are popular as they are closed under Boolean operations and determinization. There exist multiple notions of timed pushdown systems like recursive timed automata, densetime pushdown automata. We explore a generalization of visibly pushdown automata over infinite words with parity acceptance condition –in which stack elements have real valued time stamps–named dense-sta...
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