Two-Way Unary Temporal Logic over Trees
نویسندگان
چکیده
منابع مشابه
A pr 2 00 9 TWO - WAY UNARY TEMPORAL LOGIC OVER TREES
We consider a temporal logic EF + F −1 for unranked, unordered finite trees. The logic has two operators: EFϕ, which says " in some proper descendant ϕ holds " , and F −1 ϕ, which says " in some proper ancestor ϕ holds ". We present an algorithm for deciding if a regular language of unranked finite trees can be expressed in EF + F −1. The algorithm uses a characterization expressed in terms of ...
متن کاملFirst-Order Logic with Two Variables and Unary Temporal Logic
We investigate the power of first-order logic with only two variables over ω-words and finite words, a logic denoted by FO. We prove that FO can express precisely the same properties as linear temporal logic with only the unary temporal operators: “next”, “previously”, “sometime in the future”, and “sometime in the past”, a logic we denote by unary-TL. Moreover, our translation from FO to unary...
متن کاملState Complexity of Operations on Two-Way Deterministic Finite Automata over a Unary Alphabet
The paper determines the number of states in a two-way deterministic finite automaton (2DFA) over a one-letter alphabet sufficient and in the worst case necessary to represent the results of the following operations: (i) intersection of an m-state 2DFA and an n-state 2DFA requires between m + n and m + n + 1 states; (ii) union of an m-state 2DFA and an n-state 2DFA, between m + n and 2m + n + 4...
متن کاملUnary Languages Recognized by Two-Way One-Counter Automata
A two-way deterministic finite state automaton with one counter (2D1CA) is a fundamental computational model that has been examined in many different aspects since sixties, but we know little about its power in the case of unary languages. Up to our knowledge, the only known unary nonregular languages recognized by 2D1CAs are those formed by strings having exponential length, where the exponent...
متن کاملConverting Two-Way Nondeterministic Unary Automata into Simpler Automata
We show that, on inputs of length exceeding 5n, any n-state unary two-way nondeterministic 4nite automaton (2nfa) can be simulated by a (2n+2)-state quasi-sweeping 2nfa. Such a result, besides providing a “normal form” for 2nfa’s, enables us to get a subexponential simulation of unary 2nfa’s by two-way deterministic 4nite automata (2dfa’s). In fact, we prove that any n-state unary 2nfa can be s...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Logical Methods in Computer Science
سال: 2009
ISSN: 1860-5974
DOI: 10.2168/lmcs-5(3:5)2009