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arXiv · 2502.03816

Ultra-test ideals in rings with finitely generated anti-canonical algebras

Tatsuki Yamaguchi
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Abstract

When anti-canonical rings are finitely generated, we give a characterization of adjoint ideals using ultra-Frobenii, a characteristic zero analogue of Frobenius morphisms. This characterization enables us to give an alternative proof of a result of Zhuang, which states that if a ring is of klt type, then so is any of its pure subrings.

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Tatsuki Yamaguchi. 2025-02-06. Ultra-test ideals in rings with finitely generated anti-canonical algebras. https://arxiv.org/abs/2502.03816

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