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arXiv 0902.1358math.GR
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关于群的无限表示的Dehn函数

On Dehn functions of infinite presentations of groups

R. I. Grigorchuk, S. V. Ivanov

摘要:

我们引入了两种新的类型的Dehn函数的群表示,似乎更适合(比标准的Dehn函数)的无限群介绍和证明之间的基本等价性的可解性的字问题定义的一组介绍的一个可判定的定义字和属性的可计算的一个新引入的功能(这种等价性失败的标准Dehn函数)。详细阐述了这个等价性,并利用这个功能,我们得到了一个表征的有限生成群的字问题,可以解决在非确定性多项式时间。我们还给出了这些功能的上界,以及标准的Dehn函数,为两个著名的周期群,其中之一是一个无限的2-群的中间增长和其他是一个自由的伯恩赛德组足够大的指数。

英文摘要:

We introduce two new types of Dehn functions of group presentations which seem more suitable (than the standard Dehn function) for infinite group presentations and prove the fundamental equivalence between the solvability of the word problem for a group presentation defined by a decidable set of defining words and the property of being computable for one of the newly introduced functions (this equivalence fails for the standard Dehn function). Elaborating on this equivalence and making use of this function, we obtain a characterization of finitely generated groups for which the word problem can be solved in nondeterministic polynomial time. We also give upper bounds for these functions, as well as for the standard Dehn function, for two well-known periodic groups one of which is an infinite 2-group of intermediate growth and the other is a free Burnside group of sufficiently large exponent.

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。

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