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arXiv math/0007087math.GR
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不含非交换自由子群的左序群

Left ordered groups with no nonabelian free subgroups

Peter A. Linnell

摘要:

左序群何时是局部可指示的,这一问题近来引起了人们的兴趣。Bergman和Tararin证明了不是所有的左序群都是局部可指示的,但所有已知的例子都包含一个非交换自由子群。我们将证明对于一个不包含非交换自由子群的大群类,任何左序群在这个类中是局部可指示的。具体地说,这个类是最小类的群体包含NS和汤普森组的分段线性同胚的单位区间,并关闭下采取子群,商群,扩展和定向工会;这里NS是类的群体不包含一个nonabelian子半群。我们还将证明某些具有合并循环子群的自由积是左可序的。

英文摘要:

There has been interest recently concerning when a left ordered group is locally indicable. Bergman and Tararin have shown that not all left ordered groups are locally indicable, but all known examples contain a nonabelian free subgroup. We shall show for a large class of groups not containing a nonabelian free subgroup, that any left ordered group in this class is locally indicable. Specifically this class is the smallest class of groups containing NS and Thompson's group of piecewise linear homeomorphisms of the unit interval, and is closed under taking subgroups, quotient groups, extensions and directed unions; here NS is the class of groups which do not contain a nonabelian subsemigroup. We shall also show that certain free products with an amalgamated cyclic subgroup are left orderable.

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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