Chebyshev potentials, Fubini--Study metrics, and geometry of the space of Kähler metrics

Fuente: arXiv
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Auteurs principaux: Jin, Chenzi, Rubinstein, Yanir A.
Format: Preprint
Publié: 2022
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author Jin, Chenzi
Rubinstein, Yanir A.
author_facet Jin, Chenzi
Rubinstein, Yanir A.
contents The Chebyshev potential of a Kähler potential on a projective variety, introduced by Witt Nyström, is a convex function defined on the Okounkov body. It is a generalization of the symplectic potential of a torus-invariant Kähler potential on a toric variety, introduced by Guillemin, that is a convex function on the Delzant polytope. A folklore conjecture asserts that a curve of Chebyshev potentials associated to a curve in the space of Kähler potentials is linear in the time variable if and only if the latter curve is a geodesic in the Mabuchi metric. This is classically true in the special toric setting, and in general Witt Nyström established the sufficiency. The goal of this article is to disprove this conjecture. More generally, we characterize the Fubini--Study geodesics for which the conjecture is true on projective space. The proof involves explicitly solving the Monge--Ampère equation describing geodesics on the subspace of Fubini--Study metrics and computing their Chebyshev potentials.
format Preprint
id arxiv_https___arxiv_org_abs_2210_13802
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Chebyshev potentials, Fubini--Study metrics, and geometry of the space of Kähler metrics
Jin, Chenzi
Rubinstein, Yanir A.
Complex Variables
Algebraic Geometry
The Chebyshev potential of a Kähler potential on a projective variety, introduced by Witt Nyström, is a convex function defined on the Okounkov body. It is a generalization of the symplectic potential of a torus-invariant Kähler potential on a toric variety, introduced by Guillemin, that is a convex function on the Delzant polytope. A folklore conjecture asserts that a curve of Chebyshev potentials associated to a curve in the space of Kähler potentials is linear in the time variable if and only if the latter curve is a geodesic in the Mabuchi metric. This is classically true in the special toric setting, and in general Witt Nyström established the sufficiency. The goal of this article is to disprove this conjecture. More generally, we characterize the Fubini--Study geodesics for which the conjecture is true on projective space. The proof involves explicitly solving the Monge--Ampère equation describing geodesics on the subspace of Fubini--Study metrics and computing their Chebyshev potentials.
title Chebyshev potentials, Fubini--Study metrics, and geometry of the space of Kähler metrics
topic Complex Variables
Algebraic Geometry
url https://arxiv.org/abs/2210.13802