Doron Tiferet - Academia.edu (original) (raw)

Papers by Doron Tiferet

An automaton is unambiguous if for every input it has at most one accepting computation. An autom... more An automaton is unambiguous if for every input it has at most one accepting computation. An automaton is finitely (respectively, countably) ambiguous if for every input it has at most finitely (respectively, countably) many accepting computations. An automaton is boundedly ambiguous if there is k ∈ N, such that for every input it has at most k accepting computations. We consider Parity Tree Automata (PTA) and prove that the problem whether a PTA is not unambiguous (respectively, is not boundedly ambiguous, not finitely ambiguous) is co-NP complete, and the problem whether a PTA is not countably ambiguous is co-NP hard. 2012 ACM Subject Classification Theory of computation → Automata over infinite objects

An automaton is unambiguous if for every input it has at most one accepting computation. An autom... more An automaton is unambiguous if for every input it has at most one accepting computation. An automaton is finitely (respectively, countably) ambiguous if for every input it has at most finitely (respectively, countably) many accepting computations. An automaton is boundedly ambiguous if there is k ∈ N, such that for every input it has at most k accepting computations. We consider nondeterministic Büchi automata (NBA) over infinite trees and prove that it is decidable in polynomial time, whether an automaton is unambiguous, boundedly ambiguous, finitely ambiguous, or countably ambiguous. 2012 ACM Subject Classification Theory of computation → Automata over infinite objects

An automaton is unambiguous if for every input it has at most one accepting computation. An autom... more An automaton is unambiguous if for every input it has at most one accepting computation. An automaton is k-ambiguous (for k>0) if for every input it has at most k accepting computations. An automaton is boundedly ambiguous if there is k, such that for every input it has at most k accepting computations. An automaton is finitely (respectively, countably) ambiguous if for every input it has at most finitely (respectively, countably) many accepting computations. The degree of ambiguity of a regular language is defined in a natural way. A language is k-ambiguous (respectively, boundedly, finitely, countably ambiguous) if it is accepted by a k-ambiguous (respectively, boundedly, finitely, countably ambiguous) automaton. Over finite words, every regular language is accepted by a deterministic automaton. Over finite trees, every regular language is accepted by an unambiguous automaton. Over omega\omegaomega-words every regular language is accepted by an unambiguous Buchi automaton and by a dete...

Information and Computation, 2021

Abstract An automaton is unambiguous if for every input it has at most one accepting computation.... more Abstract An automaton is unambiguous if for every input it has at most one accepting computation. An automaton is finitely (respectively, countably) ambiguous if for every input it has at most finitely (respectively, countably) many accepting computations. An automaton is boundedly ambiguous if there is k ∈ N , such that for every input it has at most k accepting computations. We consider nondeterministic Buchi automata (NBA) over infinite trees and prove that it is decidable in polynomial time, whether an automaton is unambiguous, boundedly ambiguous, finitely ambiguous, or countably ambiguous.

An automaton is unambiguous if for every input it has at most one accepting computation. An autom... more An automaton is unambiguous if for every input it has at most one accepting computation. An automaton is finitely (respectively, countably) ambiguous if for every input it has at most finitely (respectively, countably) many accepting computations. An automaton is boundedly ambiguous if there is k ∈ N, such that for every input it has at most k accepting computations. We consider Parity Tree Automata (PTA) and prove that the problem whether a PTA is not unambiguous (respectively, is not boundedly ambiguous, not finitely ambiguous) is co-NP complete, and the problem whether a PTA is not countably ambiguous is co-NP hard. 2012 ACM Subject Classification Theory of computation → Automata over infinite objects

An automaton is unambiguous if for every input it has at most one accepting computation. An autom... more An automaton is unambiguous if for every input it has at most one accepting computation. An automaton is finitely (respectively, countably) ambiguous if for every input it has at most finitely (respectively, countably) many accepting computations. An automaton is boundedly ambiguous if there is k ∈ N, such that for every input it has at most k accepting computations. We consider nondeterministic Büchi automata (NBA) over infinite trees and prove that it is decidable in polynomial time, whether an automaton is unambiguous, boundedly ambiguous, finitely ambiguous, or countably ambiguous. 2012 ACM Subject Classification Theory of computation → Automata over infinite objects

An automaton is unambiguous if for every input it has at most one accepting computation. An autom... more An automaton is unambiguous if for every input it has at most one accepting computation. An automaton is k-ambiguous (for k>0) if for every input it has at most k accepting computations. An automaton is boundedly ambiguous if there is k, such that for every input it has at most k accepting computations. An automaton is finitely (respectively, countably) ambiguous if for every input it has at most finitely (respectively, countably) many accepting computations. The degree of ambiguity of a regular language is defined in a natural way. A language is k-ambiguous (respectively, boundedly, finitely, countably ambiguous) if it is accepted by a k-ambiguous (respectively, boundedly, finitely, countably ambiguous) automaton. Over finite words, every regular language is accepted by a deterministic automaton. Over finite trees, every regular language is accepted by an unambiguous automaton. Over omega\omegaomega-words every regular language is accepted by an unambiguous Buchi automaton and by a dete...

Information and Computation, 2021

Abstract An automaton is unambiguous if for every input it has at most one accepting computation.... more Abstract An automaton is unambiguous if for every input it has at most one accepting computation. An automaton is finitely (respectively, countably) ambiguous if for every input it has at most finitely (respectively, countably) many accepting computations. An automaton is boundedly ambiguous if there is k ∈ N , such that for every input it has at most k accepting computations. We consider nondeterministic Buchi automata (NBA) over infinite trees and prove that it is decidable in polynomial time, whether an automaton is unambiguous, boundedly ambiguous, finitely ambiguous, or countably ambiguous.