The topics included in this proceedings cover both mathematics and computer science. They include Codes, Free Monoids, Transformation Semigroups, Automata, Formal Languages, Word Problems, Orders and Combinatorics. Attention is paid to the algebraic theories of codes and rewriting systems, which are the key subjects that combine these two fields. The number of papers in the proceedings exceeds 45 and all papers have been refereed.

The research results published in this set of proceedings range from pure semigroup theory to theoretical computer science, in particular formal languages and automata. Contributed by internationally recognized researchers, the papers address issues in the algebraic and combinatorial theories of semigroups, the structure theory of automata, the classification theory of formal languages and codes and applications of these theories to various areas like circuit testing, coding theory, or cryptography. The underlying theme is the semigroup and automaton theories and their role in certain applications.

The research results published in this volume range from pure mathematical theory (semigroup theory, discrete mathematics, and so on) to theoretical computer science, in particular formal languages and automata. The papers are the proceedings of the Third International Colloquium on Words, Languages and Combinatorics, and they address issues in the algebraic and combinatorial theories of semigroups, words and languages, the structure theory of automata, the classification theory of formal languages and codes, and applications of these theories to various areas, like quantum and molecular computing, coding theory, and cryptography.

This book constitutes the refereed proceedings of the 13th International Conference on Combinatorics on Words, WORDS 2021, held virtually in September 2021. The 14 revised full papers presented in this book together with 2 invited talks were carefully reviewed and selected from 18 submissions. WORDS is the main conference series devoted to the mathematical theory of words. In particular, the combinatorial, algebraic and algorithmic aspects of words are emphasized. Motivations may also come from other domains such as theoretical computer science, bioinformatics, digital geometry, symbolic dynamics, numeration systems, text processing, number theory, etc.

This book constitutes the refereed proceedings of the 14th International Conference on Combinatorics on Words, WORDS 2023, held in Umeå, Sweden, during June 12–16, 2023. The 19 contributed papers presented in this book were carefully reviewed and selected from 28 submissions. In addition, the volume also contains 3 invited papers. WORDS is the main conference series devoted to combinatorics on words. This area is connected to several topics from computer science and mathematics, including string algorithms, automated proofs, discrete dynamics, number theory and, of course, classical combinatorics

This book constitutes the proceedings of the 25th International Conference on Developments in Language Theory, DLT 2021, which was held in Porto, Portugal, during August 16-20, 2021. The conference took place in an hybrid format with both in-person and online participation. The 27 full papers included in these proceedings were carefully reviewed and selected from 48 submissions. The DLT conference series provides a forum for presenting current developments in formal languages and automata. Its scope is very general and includes, among others, the following topics and areas: grammars, acceptors and transducers for words, trees and graphs; algebraic theories of automata; algorithmic, combinatorial, and algebraic properties of words and languages; variable length codes; symbolic dynamics; cellular automata; polyominoes and multidimensional patterns; decidability questions; image manipulation and compression; efficient text algorithms; relationships to cryptography, concurrency, complexity theory, and logic; bio-inspired computing; quantum computing. The book also includes 3 invited talks in full paper length.