Developments in Language Theory

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; e cient 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.

Inhalt

Invited Talks.- Morphic sequences versus automatic sequences.- Parsimonious Computational Completeness Pointlike sets and separation: a personal perspective.- Regular Papers.- A strong non-overlapping Dyck code.- Active Learning of Sequential Transducers with Side Information about the Domain.- Compositions of Constant Weighted Extended Tree Transducers.- Extremal Binary PFAs in a Cerny Family.- Variations on the Post Correspondence Problem for Free Groups.- Reducing local alphabet size in recognizable picture languages.- Properties of Graphs Specified by a Regular Language.- Balanced-by-construction regular and omega-regular languages.- Weighted Prefix Normal Words: Mind the Gap.- Two-Way Non-Uniform Finite Automata.- Integer Weighted Automata on Infinite Words.- Deciding FO2 Alternation for Automata over Finite and Infinite Words.- State Complexity of Projection on Languages Recognized by Permutation Automata and Commuting Letters.- Constrained Synchronization and Subset Synchronization Problems for Weakly Acyclic Automata.- Lyndon words formalized in Isabelle/HOL.- The Range of State Complexities of Languages Resulting from the Cascade Product-The General Case (Extended Abstract).- Second-order finite automata: expressive power and simple proofs using automatic structures.- Reversible Top-Down Syntax Analysis.- Symmetry groups of infinite words.- Bounded Languages Described by GF(2)-grammas.- Definability Results for Top-Down Tree Transducers.- The hardest LL(k) language.- Upper Bounds on Distinct Maximal (Sub-)Repetitions in Compressed Strings.- Branching Frequency and Markov Entropy of Repetition-Free Languages.- A Linear-time Simulation of Deterministic d-Limited Automata.- Caratheodory Extensions of Subclasses of Regular Languages.- Parikh Word Representable Graphs and Morphisms.