There are many open questions surrounding the characterisation of groups with context-sensitive word problem. Only in 2018 was it shown that all finitely generated virtually Abelian groups have multiple context-free word problems, and it is a long-standing open question as to where to place the word problems of hyperbolic groups in the formal language hierarchy. In this paper, we introduce a new language class called the parallel hyperedge replacement string languages, show that it contains all multiple context-free and ET0L languages, and lay down the foundations for future work that may be able to place the word problems of many hyperbolic groups in this class.

中文翻译：

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并行Hyperedge替换字符串语言

围绕上下文敏感词问题的群体表征存在许多悬而未决的问题。仅在2018年，它表明所有有限生成的虚拟阿贝尔群体都存在多个与上下文无关的单词问题，这对于将双曲群体的单词问题放在形式语言层次结构中的位置是一个长期存在的开放性问题。在本文中，我们介绍了一种新的语言类，称为并行超边缘替换字符串语言，表明它包含所有多种上下文无关和ET0L语言，并为将来的工作奠定了基础，这些工作可能会引起许多单词问题。此类中的双曲线组。