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arXiv 1409.0176math.GRmath.RT
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环上仿射Kac-Moody群的表示

Presentation of affine Kac-Moody groups over rings

Daniel Allcock

摘要:

Tits对任意的根系和任意的交换环R定义了Steinberg群和Kac-Moody群。对任意R,建立了任意秩> 2的不可约仿射根系的Steinberg群St的Curtis-Tits式表示.也就是说,St是来自Dynkin图的1-和2-节点子图的Steinberg群的直接极限。这导致了一个完全明确的介绍。利用这一点,我们证明了St是n-表示的,如果秩> 3,R是n-生成的环,或者如果秩是3,R是n-生成的子环上的模,由n个单位生成。当R是算术型戴德金整环时,相应的Kac-Moody群也有类似的结果.

英文摘要:

Tits has defined Steinberg groups and Kac-Moody groups for any root system and any commutative ring R. We establish a Curtis-Tits-style presentation for the Steinberg group St of any rank > 2 irreducible affine root system, for any R. Namely, St is the direct limit of the Steinberg groups coming from the 1- and 2-node subdiagrams of the Dynkin diagram. This leads to a completely explicit presentation. Using this we show that St is finitely presented if the rank is > 3 and R is finitely generated as a ring, or if the rank is 3 and R is finitely generated as a module over a subring generated by finitely many units. Similar results hold for the corresponding Kac-Moody groups when R is a Dedekind domain of arithmetic type.

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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