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arXiv · 2312.01012

The volume of a divisor and cusp excursions of geodesics in hyperbolic manifolds

Simion Filip·John Lesieutre·Valentino Tosatti
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Abstract

We give a complete description of the behavior of the volume function at the boundary of the pseudoeffective cone of certain Calabi-Yau complete intersections known as Wehler N-folds. We find that the volume function exhibits a pathological behavior when N>=3, we obtain examples of a pseudoeffective R-divisor D for which the volume of D+sA, with s small and A ample, oscillates between two powers of s, and we deduce the sharp regularity of this function answering a question of Lazarsfeld. We also show that h^0(X,[mD]+A) displays a similar oscillatory behavior as m increases, showing that several notions of numerical dimensions of D do not agree and disproving a conjecture of Fujino. We accomplish this by relating the behavior of the volume function along a segment to the visits of a corresponding hyperbolic geodesics to the cusps of a hyperbolic manifold.

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Simion Filip, John Lesieutre, Valentino Tosatti. 2023-12-02. The volume of a divisor and cusp excursions of geodesics in hyperbolic manifolds. https://doi.org/10.1090/jag%2F851

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