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arXiv 2602.22947math.AG
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关于Fujino和Sato猜想的再探讨

On a conjecture of Fujino and Sato

Università di Milano Bicocca(米兰比可卡大学)

Michele Rossi

AI总结:

本文通过二次扇理论,证明非射影有理数极小弱Mori Dream空间可通过D-翻转转化为射影Mori Dream空间,并提供简短的证明方法。

摘要:

我们重新审视Fujino-Sato关于完全非射影有理数极小的托里克品种及其通过翻转的猜想性分解的结果。我们证明他们的主要结果可以有简短的概念性证明,一旦通过GKZ(二次扇)分解移动锥来组织小的有理数极小修改,就无需对维度和皮卡数施加任何限制,这基于Cox环的一般理论和 Mori Dream Spaces。此外,我们通过证明一个类似的陈述扩展了这一观点,超越托里克情况,即任何非射影的有理数极小弱Mori Dream空间都存在一个除子D和一个D-翻转到(射影)Mori Dream空间。我们的方法突显了二次扇中房间和壁穿越在这些构造中的统一框架作用。

英文摘要:

We revisit results of Fujino--Sato on complete non-projective $\mathbb Q$-factorial toric varieties and their conjectural factorization by flips. We show that their main results admit short conceptual proofs, avoiding any restriction on the dimension and the Picard number, from the general theory of Cox rings and Mori Dream Spaces, once one organizes small $\mathbb Q$-factorial modifications via the GKZ (secondary fan) decomposition of the moving cone. Moreover, we extend this viewpoint beyond the toric case by proving an analogous statement for complete $\mathbb Q$-factorial weak Mori Dream Spaces: any non-projective such variety admits a divisor $D$ and a $D$-flip to a (projective) Mori Dream Space. Our approach highlights the role of chambers and wall-crossing in the secondary fan as a unifying framework for these constructions.

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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