arXiv subjects

Kairui Xu

Publications and source records attributed to Kairui Xu.

3 recordsLinked to original sources

arXiv2025

Parabolic frequency monotonicity for two nonlinear equations under Ricci flow

In this paper, we consider the parabolic frequency for positive solutions of two nonlinear parabolic equations under the Ricci flow on closed manifolds. We obtain the monotonicity of parabolic frequency for the solution of two nonlinear parabolic equations with bounded Ricci curvature, then we apply the parabolic frequency monotonicity to get some integral type Harnack inequalities and we use -K1 instead of the lower bound 0 of Ricci curvature from Theorem 4.3 in 16, where K1 is any positive constant.

math.DG↗

arXiv2025

Gradient estimates and parabolic frequency under the Laplacian G_2 flow

In this paper, we consider the Laplacian G_2 flow on a closed seven-dimensional manifold M with a closed G_2-structure. We first obtain the gradient estimates of positive solutions of the heat equation under the Laplacian G_2 flow and then we get the Harnack inequality on spacetime. As an application, we prove the monotonicity for positive solutions of the heat equation with bounded Ricci curvature, and get the integral-type Harnack inequality. Besides, we prove the monotonicity of parabolic frequency for positive solutions of the linear heat equation with bounded Bakry-Emery Ricci curvature, and then obtain the backward uniqueness.

math.DG↗

arXiv2022

Parabolic frequency monotonicity on Ricci flow and Ricci-harmonic flow with bounded curvatures

In this paper, we study the monotonicity of parabolic frequency motivated by \cite{frequency on RF} under the Ricci flow and the Ricci-harmonic flow on manifolds. Here we consider two cases: one is the monotonicity of parabolic frequency for the solution of linear heat equation with bounded Bakry-Émery Ricci curvature, and another case is the monotonicity of parabolic frequency for the solution of heat equation with bounded Ricci curvature.

math.DG↗