字符串重写系统：简要介绍与开放问题示例
String Rewriting Systems: Brief Introduction and Sample of Open Problems
AI总结：
本文整合作者多年为研究生《形式化方法》课程编写的讲义内容，更新参考文献以反映近年进展，并给出字符串重写系统领域截至当时未解决的开放问题示例。
AI中文摘要：
本文整合了作者数十年间为研究生一年级课程（通常名为《形式化方法》，涵盖数理逻辑与理论计算机科学的诸多其他主题）编写的不同讲义的小部分内容。合并材料后，作者更新了参考文献，并调整了文本以反映 intervening 年间取得的进展。最后一节中的开放问题示例是截至本文撰写之日仍未解决的特殊案例的小集合。
英文摘要：
This document is the result of pulling together small parts of different lecture notes I have written over several decades for first-year graduate-level courses -- typically with the title Formal Methods -- which included many other topics of mathematical logic and theoretical computer science. After combining these materials, I updated the references and adjusted the text to account for progress accomplished in the intervening years. The sample of open problems in the last section is a small collection of special cases that are still unresolved up until the date of this writing.
