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We survey permutation-based methods for approximate k-nearest neighbor search. In these methods, every data point is represented by a ranked list of pivots sorted by the distance to this point. Such ranked lists are called permutations. The…

Machine Learning · Computer Science 2016-11-01 Bilegsaikhan Naidan , Leonid Boytsov , Eric Nyberg

Universal cycle for $k$-permutations is a cyclic arrangement in which each $k$-permutation appears exactly once as $k$ consecutive elements. Enumeration problem of universal cycles for $k$-permutations is discussed and one new enumerating…

Combinatorics · Mathematics 2021-11-30 Zuling Chang , Jie Xue

We consider a class of pattern matching problems where a normalising transformation is applied at every alignment. Normalised pattern matching plays a key role in fields as diverse as image processing and musical information processing…

Data Structures and Algorithms · Computer Science 2015-03-19 Ayelet Butman , Peter Clifford , Raphael Clifford , Markus Jalsenius , Noa Lewenstein , Benny Porat , Ely Porat , Benjamin Sach

We consider the problem of counting all $k$-vertex subgraphs in an input graph, for any constant $k$. This problem (denoted sub-cnt$_k$) has been studied extensively in both theory and practice. In a classic result, Chiba and Nishizeki…

Data Structures and Algorithms · Computer Science 2019-12-02 Suman K. Bera , Noujan Pashanasangi , C. Seshadhri

An occurrence of a classical pattern p in a permutation \pi is a subsequence of \pi whose letters are in the same relative order (of size) as those in p. In an occurrence of a generalized pattern, some letters of that subsequence may be…

Combinatorics · Mathematics 2008-05-31 Einar Steingrimsson

We introduce a new permutation statistic, namely, the number of cycles of length $q$ consisting of consecutive integers, and consider the distribution of this statistic among the permutations of $\{1,2,...,n\}$. We determine explicit…

Combinatorics · Mathematics 2015-03-17 Richard A. Brualdi , Emeric Deutsch

A type system combining type application, constants as types, union types (associative, commutative and idempotent) and recursive types has recently been proposed for statically typing path polymorphism, the ability to define functions that…

Logic in Computer Science · Computer Science 2020-06-30 Juan Edi , Andrés Viso , Eduardo Bonelli

The circular peak set of a permutation $\sigma$ is the set $\{\sigma(i)\mid \sigma(i-1)<\sigma(i)>\sigma(i+1)\}$. In this paper, we focus on the enumeration problems for permutations by circular peak sets. Let $cp_n(S)$ denote the number of…

Combinatorics · Mathematics 2008-06-05 Pierre Bouchard , Hungyung Chang , Jun Ma , Jean Yeh

We introduce Permutation and Structured Perturbation Inference (PSPI), a new problem formulation that abstracts many graph matching tasks that arise in systems biology. PSPI can be viewed as a robust formulation of the permutation inference…

Artificial Intelligence · Computer Science 2021-04-05 Raghvendra Mall , Shameem A. Parambath , Han Yufei , Ting Yu , Sanjay Chawla

The goal of the paper is to give fine-grained hardness results for the Subgraph Isomorphism (SI) problem for fixed size induced patterns $H$, based on the $k$-Clique hypothesis that the current best algorithms for Clique are optimal. Our…

Computational Complexity · Computer Science 2022-09-07 Mina Dalirrooyfard , Virginia Vassilevska Williams

The decades-old Pattern Matching with Edits problem, given a length-$n$ string $T$ (the text), a length-$m$ string $P$ (the pattern), and a positive integer $k$ (the threshold), asks to list all fragments of $T$ that are at edit distance at…

Data Structures and Algorithms · Computer Science 2024-10-10 Tomasz Kociumaka , Jakob Nogler , Philip Wellnitz

This paper presents a comprehensive study of algorithms for maintaining the number of all connected four-vertex subgraphs in a dynamic graph. Specifically, our algorithms maintain the number of paths of length three in deterministic…

Data Structures and Algorithms · Computer Science 2022-03-18 Kathrin Hanauer , Monika Henzinger , Qi Cheng Hua

We revisit Hopcroft's problem and related fundamental problems about geometric range searching. Given $n$ points and $n$ lines in the plane, we show how to count the number of point-line incidence pairs or the number of point-above-line…

Computational Geometry · Computer Science 2022-06-23 Timothy M. Chan , Da Wei Zheng

In a uniform random permutation \Pi of [n] := {1,2,...,n}, the set of elements k in [n-1] such that \Pi(k+1) = \Pi(k) + 1 has the same distribution as the set of fixed points of \Pi that lie in [n-1]. We give three different proofs of this…

Probability · Mathematics 2014-04-29 Persi Diaconis , Steven N. Evans , Ron Graham

Let $\pi_n$ be a uniformly chosen random permutation on $[n]$. The authors of [2] showed that the expected number of distinct consecutive patterns of all lengths $k\in\{1,2,\ldots,n\}$ in $\pi_n$ was $\frac{n^2}{2}(1-o(1))$ as $n\to\infty$,…

Combinatorics · Mathematics 2026-03-31 Verónica Borrás-Serrano , Isabel Byrne , Anant Godbole , Nathaniel Veimau

We introduce consecutive-pattern-avoiding stack-sorting maps $\text{SC}_\sigma$, which are natural generalizations of West's stack-sorting map $s$ and natural analogues of the classical-pattern-avoiding stack-sorting maps $s_\sigma$…

Combinatorics · Mathematics 2020-08-28 Colin Defant , Kai Zheng

The graph of overlapping permutations is defined in a way analogous to the De Bruijn graph on strings of symbols. That is, for every permutation $\pi = \pi_{1} \pi_{2} ... \pi_{n+1}$ there is a directed edge from the standardization of…

Combinatorics · Mathematics 2014-10-08 Richard Ehrenborg , Sergey Kitaev , Einar Steingrimsson

In this paper, we study permutations $\pi \in S_n$ with exactly $m$ transpositions. In particular, we are interested in the expected value of $\pi(1)$ when such permutations are chosen uniformly at random. When $n$ is even, this expected…

Combinatorics · Mathematics 2021-12-13 Peter Kagey

In this article, we describe an algorithm to determine whether a permutation class C given by a finite basis B of excluded patterns contains a finite number of simple permutations. This is a continuation of the work initiated in [Brignall,…

Combinatorics · Mathematics 2014-12-09 Frédérique Bassino , Mathilde Bouvel , Adeline Pierrot , Dominique Rossin

A permutation $\pi$ is said to be {\em Dumont permutations of the first kind} if each even integer in $\pi$ must be followed by a smaller integer, and each odd integer is either followed by a larger integer or is the last element of $\pi$…

Combinatorics · Mathematics 2007-05-23 T. Mansour
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