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arXiv · 2208.09960

The Stochastic Schwarz lemma on K\"ahler Manifolds by Couplings and Its Applications

Myeongju Chae·Gunhee Cho·Maria Gordina·Guang Yang
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Abstract

We first provide a stochastic formula for the Carath\'eodory distance in terms of general Markovian couplings and prove a comparison result between the Carath\'eodory distance and the complete K\"ahler metric with a negative lower curvature bound using the Kendall-Cranston coupling. This probabilistic approach gives a version of the Schwarz lemma on complete non-compact K\"ahler manifolds with a further decomposition Ricci curvature into the orthogonal Ricci curvature and the holomorphic sectional curvature, which cannot be obtained by using Yau--Royden's Schwarz lemma. We also prove coupling estimates on quaternionic K\"ahler manifolds. As a byproduct, we obtain an improved gradient estimate of positive harmonic functions on K\"ahler manifolds and quaternionic K\"ahler manifolds under lower curvature bounds.

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Myeongju Chae, Gunhee Cho, Maria Gordina, Guang Yang. 2022-08-21. The Stochastic Schwarz lemma on K\"ahler Manifolds by Couplings and Its Applications. https://arxiv.org/abs/2208.09960

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