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arXiv 1807.01009math.AG
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一般环上仿射群方案的表示

Representations of Affine Group Schemes Over General Rings

Giulia Battiston, Matthieu Romagny

摘要:

在所有的仿射,平坦的,非线性提出的群计划,我们专注于那些是纯的,这包括所有的群,这是一个有限的局部自由群的扩展与连接纤维的一组。证明了在任意基环上,纯群概型有一个满足分解性质的分类空间,有一个到GLn的嵌入,有一个其有限型表示范畴的张量生成元,并且可以从其射影有限型表示范畴重构.在一个Artin基环的情况下,对于所有仿射的,平坦的,群表示的群概型也是如此,这回答了康拉德的一个问题。我们还证明了纯群在任意基概型上由闭纯子群所生成的子群是Zerkiki-局部拟投射的。这回答了雷诺的一个问题,在仿射群的情况下。我们提供各种应用程序。

英文摘要:

Among all affine, flat, finitely presented group schemes, we focus on those that are pure, this includes all groups which are extensions of a finite locally free group by a group with connected fibres. We prove that over an arbitrary base ring, pure group schemes have a classifying space satisfying the resolution property, an embedding into some GLn, a tensor generator for their category of finite type representations, and can be reconstructed from their category of projective finite type representations. In the case of an Artinian base ring, the same is true for all affine, flat, finitely presented group schemes, this answers a question of Conrad. We also prove that quotients of pure groups by closed pure subgroups over an arbitrary base scheme are Zariski-locally quasi-projective. This answers a question of Raynaud, in the case of affine groups. We give various applications.

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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