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We study the sweep complexity of DFA in one-way jumping mode answering several questions posed earlier. This measure is the number of times in the worst case that such machines have to return to the beginning of their input after having…

Formal Languages and Automata Theory · Computer Science 2023-08-15 Szilárd Zsolt Fazekas , Robert Mercaş

We construct a probabilistic finite automaton (PFA) with 7 states and an input alphabet of 5 symbols for which the PFA Emptiness Problem is undecidable. The only input for the decision problem is the starting distribution. For the proof, we…

Formal Languages and Automata Theory · Computer Science 2024-12-09 Günter Rote

The value 1 problem is a decision problem for probabilistic automata over finite words: given a probabilistic automaton A, are there words accepted by A with probability arbitrarily close to 1? This problem was proved undecidable recently.…

Formal Languages and Automata Theory · Computer Science 2012-01-27 Nathanaël Fijalkow , Hugo Gimbert , Youssouf Oualhadj

Multi-letter {\it quantum finite automata} (QFAs) were a quantum variant of classical {\it one-way multi-head finite automata} (J. Hromkovi\v{c}, Acta Informatica 19 (1983) 377-384), and it has been shown that this new one-way QFAs…

Formal Languages and Automata Theory · Computer Science 2010-11-01 Daowen Qiu , Xiangfu Zou , Lvzhou Li , Paulo Mateus

We introduce a new complexity measure for finite strings using probabilistic finite-state automata (PFAs), in the same spirit as existing notions employing DFAs and NFAs, and explore its properties. The PFA complexity $A_P(x)$ is the least…

Formal Languages and Automata Theory · Computer Science 2024-06-04 Kenneth Gill

In automata theory, the quantum computation has been widely examined for finite state machines, known as quantum finite automata (QFAs), and less attention has been given to the QFAs augmented with counters or stacks. Moreover, to our…

Computational Complexity · Computer Science 2011-05-10 Abuzer Yakaryilmaz

1-way quantum finite state automata are reversible in nature, which greatly reduces its accepting property. In fact, the set of languages accepted by 1-way quantum finite automata is a proper subset of regular languages. We introduce 2-tape…

Formal Languages and Automata Theory · Computer Science 2016-07-05 Debayan Ganguly , Kumar Sankar Ray

Given an order of the underlying alphabet we can lift it to the states of a finite deterministic automaton: to compare states we use the order of the strings reaching them. When the order on strings is the co-lexicographic one \emph{and}…

Formal Languages and Automata Theory · Computer Science 2022-03-24 Giovanna D'Agostino , Davide Martincigh , Alberto Policriti

Approximation algorithms for classical constraint satisfaction problems are one of the main research areas in theoretical computer science. Here we define a natural approximation version of the QMA-complete local Hamiltonian problem and…

Quantum Physics · Physics 2016-10-25 Sevag Gharibian , Julia Kempe

A quantum constraint problem is a frustration-free Hamiltonian problem: given a collection of local operators, is there a state that is in the ground state of each operator simultaneously? It has previously been shown that these problems…

Quantum Physics · Physics 2021-07-22 Alex Meiburg

History-deterministic automata are those in which nondeterministic choices can be correctly resolved stepwise: there is a strategy to select a continuation of a run given the next input letter so that if the overall input word admits some…

Formal Languages and Automata Theory · Computer Science 2026-04-01 Soumyajit Paul , David Purser , Sven Schewe , Qiyi Tang , Patrick Totzke , Di-De Yen

Automata over infinite words, also known as omega-automata, play a key role in the verification and synthesis of reactive systems. The spectrum of omega-automata is defined by two characteristics: the acceptance condition (e.g. B\"uchi or…

Formal Languages and Automata Theory · Computer Science 2021-01-01 Rayna Dimitrova , Bernd Finkbeiner , Hazem Torfah

In the literature, there exist several quantum finite automata (QFA) models with both quantum and classical states. These models are of particular interest,as they show praiseworthy advantages over the fully quantum models in some…

Formal Languages and Automata Theory · Computer Science 2015-06-30 Lvzhou Li , Yuan Feng

A quantum finite-state automaton (QFA) is a theoretical model designed to simulate the evolution of a quantum system with finite memory in response to sequential input strings. We define the language of a QFA as the set of strings that lead…

Computation and Language · Computer Science 2024-07-04 SeungYeop Baik , Sicheol Sung , Yo-Sub Han

The fixed template Promise Constraint Satisfaction Problem (PCSP) is a recently proposed significant generalization of the fixed template CSP, which includes approximation variants of satisfiability and graph coloring problems. All the…

Computational Complexity · Computer Science 2019-09-12 Libor Barto

In this note, we generalize the results of arXiv:0901.2703v1 We show that all one-way quantum finite automaton (QFA) models that are at least as general as Kondacs-Watrous QFA's are equivalent in power to classical probabilistic finite…

Computational Complexity · Computer Science 2010-09-20 Abuzer Yakaryilmaz , A. C. Cem Say

We consider the value 1 problem for probabilistic automata over finite words: it asks whether a given probabilistic automaton accepts words with probability arbitrarily close to 1. This problem is known to be undecidable. However, different…

Formal Languages and Automata Theory · Computer Science 2017-09-12 Nathanaël Fijalkow

This paper studies the complexity of operations on finite automata and the complexity of their decision problems when the alphabet is unary. Let $n$ denote the maximum of the number of states of the input finite automata considered in the…

Formal Languages and Automata Theory · Computer Science 2024-12-16 Wojciech Czerwiński , Maciej Dębski , Tomasz Gogasz , Gordon Hoi , Sanjay Jain , Michał Skrzypczak , Frank Stephan , Christopher Tan

In the field of computational logic, two classes of finite automata are considered fundamental: deterministic and nondeterministic automata (DFAs and NFAs). In a more fine-grained approach three natural intermediate classes were introduced,…

Formal Languages and Automata Theory · Computer Science 2025-07-22 Karolina Drabik , Anita Dürr , Fabian Frei , Filip Mazowiecki , Karol Węgrzycki

Quantitative analysis of computing systems is an emerging area in automated formal analysis. Such properties address aspects such as costs and rewards, quality measures, resource consumption, distance metrics, etc. Existing solutions for…

Formal Languages and Automata Theory · Computer Science 2020-10-06 Suguman Bansal