Problems around the Stanley-Wilf Limits of Permutation

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Journal Title

Journal ISSN

Volume Title

Perustieteiden korkeakoulu | Master's thesis

Date

2023-08-22

Department

Major/Subject

Applied Mathematics

Mcode

SCI3053

Degree programme

Master’s Programme in Mathematics and Operations Research

Language

en

Pages

47

Series

Abstract

The Theory of Matrix Avoidance explores the problem of determining the maximum number of 1-entries in an 𝑛 × 𝑛 binary matrix that avoids a fixed pattern 𝑃. For permutation matrices, the Furedi-Hajnal conjecture posits a linear relationship between this number, known as extremal function of 𝑛, and the matrix size 𝑛. This conjecture was initially proven by Marcus and Tardos, and subsequently, the linear constant was further improved. Another class of matrices, known as light matrices, exhibits a quasi-linear extremal function. Although, the proof for this class relies on the connection between pattern avoidance and the theory of Davenport-Schinzel sequences. This thesis presents a proof for light matrices in terms of matrices without applying known results from connected topics, followed by an alternative proof for the Furedi-Hajnal conjecture. By addressing these topics, this research contributes to the understanding of matrix avoidance and its implications for different matrix classes.

Description

Supervisor

Chalermsook, Parinya

Thesis advisor

Yingchareonthawornchai, Sorrachai

Keywords

permutation avoidance, forbidden matrix, Stanley-Wilf limit, Furedi-Hajnal limit, light matrix

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