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Let $A$ be an $n\times n$ random matrix whose entries are i.i.d. with mean $0$ and variance $1$. We present a deterministic polynomial time algorithm which, with probability at least $1-2\exp(-\Omega(\epsilon n))$ in the choice of $A$,…

Probability · Mathematics 2020-12-02 Vishesh Jain , Ashwin Sah , Mehtaab Sawhney

This papers contains two results concerning random $n \times n$ Bernoulli matrices. First, we show that with probability tending to one the determinant has absolute value $\sqrt {n!} \exp(O(\sqrt(n log n)))$. Next, we prove a new upper…

Combinatorics · Mathematics 2008-07-01 Terence Tao , Van Vu

This paper investigates to what extent one can improve reinforcement learning algorithms. Our study is split in three parts. First, our analysis shows that the classical asymptotic convergence rate $O(1/\sqrt{N})$ is pessimistic and can be…

Machine Learning · Computer Science 2021-10-25 Othmane Mounjid , Charles-Albert Lehalle

We show that if a semisimple synchronizing automaton with $n$ states has a minimal reachable non-unary subset of cardinality $r\ge 2$, then there is a reset word of length at most $(n-1)D(2,r,n)$, where $D(2,r,n)$ is the $2$-packing number…

Formal Languages and Automata Theory · Computer Science 2023-02-06 Emanuele Rodaro

We present an infinite series of $n$-state Eulerian automata whose reset words have length at least $(n^2-3)/2$. This improves the current lower bound on the length of shortest reset words in Eulerian automata. We conjecture that…

Formal Languages and Automata Theory · Computer Science 2016-08-04 Marek Szykuła , Vojtěch Vorel

We have improved an algorithm generating synchronizing automata with a large length of the shortest reset words. This has been done by refining some known results concerning bounds on the reset length. Our improvements make possible to…

Formal Languages and Automata Theory · Computer Science 2016-07-15 Andrzej Kisielewicz , Jakub Kowalski , Marek Szykuła

Motivated by the \v{C}ern\'y conjecture for automata, we introduce the concept of monoidal automata, which allows the formulation of the \v{C}ern\'y conjecture for monoids. We show upper bounds on the reset threshold of monoids with certain…

Formal Languages and Automata Theory · Computer Science 2025-09-16 Igor Rystsov , Marek Szykuła

A $d$-limited automaton is a Turing machine that may rewrite each input cell at most~$d$ times. Hibbard (1967) showed that for every $d \geq 2$ such automata recognize all context-free languages and that deterministic $d$-limited automata…

Formal Languages and Automata Theory · Computer Science 2025-09-01 Alexander Rubtsov

Uniform stability of a learning algorithm is a classical notion of algorithmic stability introduced to derive high-probability bounds on the generalization error (Bousquet and Elisseeff, 2002). Specifically, for a loss function with range…

Machine Learning · Computer Science 2019-03-19 Vitaly Feldman , Jan Vondrak

The largest known reset thresholds for DFAs are equal to $(n-1)^2$, where $n$ is the number of states. This is conjectured to be the maximum possible. PFAs (with partial transition function) can have exponentially large reset thresholds.…

Formal Languages and Automata Theory · Computer Science 2023-04-18 Stijn Cambie , Michiel de Bondt , Henk Don

Squares (fragments of the form $xx$, for some string $x$) are arguably the most natural type of repetition in strings. The basic algorithmic question concerning squares is to check if a given string of length $n$ is square-free, that is,…

Data Structures and Algorithms · Computer Science 2023-03-14 Jonas Ellert , Paweł Gawrychowski , Garance Gourdel

We estimate the minimum number of distance queries that is sufficient to reconstruct the binomial random graph $G(n,p)$ with constant diameter with high probability. We get a tight (up to a constant factor) answer for all $p>n^{-1+o(1)}$…

Combinatorics · Mathematics 2024-07-31 Michael Krivelevich , Maksim Zhukovskii

Motivated by problems in controlled experiments, we study the discrepancy of random matrices with continuous entries where the number of columns $n$ is much larger than the number of rows $m$. Our first result shows that if $\omega(1) = m =…

Discrete Mathematics · Computer Science 2020-11-10 Paxton Turner , Raghu Meka , Philippe Rigollet

We consider the problem of sketching the $p$-th frequency moment of a vector, $p>2$, with multiplicative error at most $1\pm \epsilon$ and \emph{with high confidence} $1-\delta$. Despite the long sequence of work on this problem, tight…

Data Structures and Algorithms · Computer Science 2018-05-29 Sumit Ganguly , David P. Woodruff

Every language recognized by a non-deterministic finite automaton can be recognized by a deterministic automaton, at the cost of a potential increase of the number of states, which in the worst case can go from $n$ states to $2^n$ states.…

Formal Languages and Automata Theory · Computer Science 2025-02-05 Arnaud Carayol , Philippe Duchon , Florent Koechlin , Cyril Nicaud

We follow language theoretic approach to synchronizing automata and \v{C}ern\'{y}'s conjecture initiated in a series of recent papers. We find a precise lower bound for the reset complexity of a principal ideal languages. Also we show a…

Formal Languages and Automata Theory · Computer Science 2014-12-23 Marina Maslennikova , Emanuele Rodaro

Let $g$, $h$ be a random pair of generators of $G=Sym(n)$ or $G=Alt(n)$. We show that, with probability tending to $1$ as $n\to \infty$, (a) the diameter of $G$ with respect to $S = \{g,h,g^{-1},h^{-1}\}$ is at most $O(n^2 (\log n)^c)$, and…

Group Theory · Mathematics 2014-03-11 Harald A. Helfgott , Ákos Seress , Andrzej Zuk

A Random Access query to a string $T\in [0..\sigma)^n$ asks for the character $T[i]$ at a given position $i\in [0..n)$. In $O(n\log\sigma)$ bits of space, this fundamental task admits constant-time queries. While this is optimal in the…

Data Structures and Algorithms · Computer Science 2026-05-13 Anouk Duyster , Tomasz Kociumaka

We assume the permutation $\pi$ is given by an $n$-element array in which the $i$-th element denotes the value $\pi(i)$. Constructing its inverse in-place (i.e. using $O(\log{n})$ bits of additional memory) can be achieved in linear time…

Data Structures and Algorithms · Computer Science 2020-04-22 Grzegorz Guśpiel

Most slowly synchronizing automata over binary alphabets are circular, i.e., containing a letter permuting the states in a single cycle, and their set of synchronizing words has maximal state complexity, which also implies complete…

Formal Languages and Automata Theory · Computer Science 2020-12-01 Stefan Hoffmann