有限半群识别的语言，以及它们对树和图等对象的推广，重点是一元二阶逻辑中的可定义性
Languages recognised by finite semigroups, and their generalisations to objects such as trees and graphs, with an emphasis on definability in monadic second-order logic
摘要：
这些是关于正则语言的代数方法的课堂讲稿。经典的代数方法是针对有限字的;它使用半群而不是自动机。然而，代数方法可以扩展到单词以外的结构，例如~无限的单词，或者树，或者图这本书的目的是描述代数方法的方式，涵盖这些扩展。
英文摘要：
These are lecture notes on the algebraic approach to regular languages. The classical algebraic approach is for finite words; it uses semigroups instead of automata. However, the algebraic approach can be extended to structures beyond words, e.g.~infinite words, or trees or graphs. The purpose of this book is to describe the algebraic approach in a way that covers these extensions.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
