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A word $\sigma=\sigma_1...\sigma_n$ over the alphabet $[k]=\{1,2,...,k\}$ is said to be {\em smooth} if there are no two adjacent letters with difference greater than 1. A word $\sigma$ is said to be {\em smooth cyclic} if it is a smooth…

Combinatorics · Mathematics 2008-09-04 Arnold Knopfmacher , Toufik Mansour , Augustine Munagi , Helmut Prodinger

We present sufficient conditions for when an ordering of universal cycles $\alpha_1, \alpha_2, \ldots, \alpha_m$ for disjoint sets $\mathbf{S}_1, \mathbf{S}_2, \ldots , \mathbf{S}_m$ can be concatenated together to obtain a universal cycle…

Combinatorics · Mathematics 2018-06-25 Daniel Gabric , Joe Sawada

Motivated by the change-making problem, we extend the notion of greediness to sets of positive integers not containing the element $1$, and from there to numerical semigroups. We provide an algorithm to determine if a given set (not…

Combinatorics · Mathematics 2024-12-17 Hebert Pérez-Rosés , José Miguel Serradilla-Merinero , Maria Bras-Amorós

Clustering problems such as $k$-means and $k$-median are staples of unsupervised learning, and many algorithmic techniques have been developed to tackle their numerous aspects. In this paper, we focus on the class of greedy approximation…

Data Structures and Algorithms · Computer Science 2025-10-30 Max Dupré la Tour , David Saulpic

A universal cycle, or u-cycle, for a given set of words is a circular word that contains each word from the set exactly once as a contiguous subword. The celebrated de Bruijn sequences are a particular case of such a u-cycle, where a set in…

Combinatorics · Mathematics 2019-08-06 Herman Z. Q. Chen , Sergey Kitaev , Brian Y. Sun

The change-making problem consists of representing a certain amount of money with the least possible number of coins, from a given, pre-established set of denominations. The greedy algorithm works by choosing the coins of largest possible…

Combinatorics · Mathematics 2025-07-14 Hebert Pérez-Rosés

Let ${\mathcal C}$ be a proper minor-closed family of graphs. We present a randomized algorithm that given a graph $G \in {\mathcal C}$ with $n$ vertices, finds a simple cycle of size $k$ in $G$ (if exists) in $2^{O(k)}n$ time. The…

Data Structures and Algorithms · Computer Science 2020-08-10 Raphael Yuster

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

In a finite undirected simple graph, a {\it chordless cycle} is an induced subgraph which is a cycle. We propose two algorithms to enumerate all chordless cycles of such a graph. Compared to other similar algorithms, the proposed algorithms…

Data Structures and Algorithms · Computer Science 2014-12-01 Elisângela Silva Dias , Diane Castonguay , Humberto Longo , Walid Abdala Rfaei Jradi

An orientable sequence of order $n$ over an alphabet $\{0,1,\ldots, k{-}1\}$ is a cyclic sequence such that each length-$n$ substring appears at most once \emph{in either direction}. When $k= 2$, efficient algorithms are known to construct…

Discrete Mathematics · Computer Science 2024-07-10 Daniel Gabrić , Joe Sawada

A $t$-spanner of a graph is a subgraph that $t$-approximates pairwise distances. The greedy algorithm is one of the simplest and most well-studied algorithms for constructing a sparse spanner: it computes a $t$-spanner with $n^{1+O(1/t)}$…

Data Structures and Algorithms · Computer Science 2023-08-03 Bernhard Haeupler , D Ellis Hershkowitz , Zihan Tan

This paper introduces a greedy parser based on neural networks, which leverages a new compositional sub-tree representation. The greedy parser and the compositional procedure are jointly trained, and tightly depends on each-other. The…

Machine Learning · Computer Science 2015-04-14 Joël Legrand , Ronan Collobert

The reconfiguration problem for homomorphisms of digraphs to a reflexive digraph cycle, which amounts to deciding if a `reconfiguration graph' is connected, is known to by polynomially time solvable via a greedy algorithm based on certain…

Combinatorics · Mathematics 2025-03-19 David Emmanuel Pazmiño Pullas , Mark Siggers

We examine the class of languages that can be defined entirely in terms of provability in an extension of the sorted type theory (Ty_n) by embedding the logic of phonologies, without introduction of special types for syntactic entities.…

Computation and Language · Computer Science 2011-02-28 Victor Gluzberg

Classic cycle-joining techniques have found widespread application in creating universal cycles for a diverse range of combinatorial objects, such as shorthand permutations, weak orders, orientable sequences, and various subsets of $k$-ary…

Combinatorics · Mathematics 2024-07-18 J. Sawada , J. Sears , A. Trautrim , A. Williams

We show that the minimum number of orientations of the edges of the n-vertex complete graph having the property that every triangle is made cyclic in at least one of them is $\lceil\log_2(n-1)\rceil$. More generally, we also determine the…

Combinatorics · Mathematics 2015-02-25 Zita Helle , Gábor Simonyi

Sequence models are a critical component of modern NLP systems, but their predictions are difficult to explain. We consider model explanations though rationales, subsets of context that can explain individual model predictions. We find…

Computation and Language · Computer Science 2021-11-19 Keyon Vafa , Yuntian Deng , David M. Blei , Alexander M. Rush

Let $k\ge 2$. We prove that the characteristic sequence of a regular language over a $k$-letter alphabet is $k$-automatic. More generally, if $t\ge 2$ and $t,k$ are multiplicatively dependent, we show that the characteristic sequence of a…

Formal Languages and Automata Theory · Computer Science 2018-07-24 Michel Rigo , Robert Underwood

In this paper, we introduce a method of constructing Universal Cycles on sets by taking "sums" and "products" of smaller cycles. We demonstrate this new approach by proving that if there exist Universal Cycles on the 4-subsets of [18] and…

Combinatorics · Mathematics 2013-04-25 Yevgeniy Rudoy

We study the problem of cutting a length-$n$ string of positive real numbers into $k$ pieces so that every piece has sum at least $b$. The problem can also be phrased as transforming such a string into a new one by merging adjacent numbers.…

Data Structures and Algorithms · Computer Science 2023-09-29 Yinqi Cai