The hyperbolic geometric flow on Riemann surfaces

TL;DR

This paper investigates the hyperbolic geometric flow on Riemann surfaces, demonstrating conditions for global existence and bounded curvature, and comparing its properties and advantages over Ricci flow.

Contribution

The authors establish conditions for global existence of solutions and bounded curvature in hyperbolic geometric flow, and highlight its potential to replace surgery techniques used in Ricci flow.

Findings

Global solutions exist with suitable initial velocities.

Solutions can blow up if initial conditions are not met.

Hyperbolic flow may avoid surgery by choosing initial velocities.

Abstract

In this paper the authors study the hyperbolic geometric flow on Riemann surfaces. This new nonlinear geometric evolution equation was recently introduced by the first two authors motivated by Einstein equation and Hamilton's Ricci flow. We prove that, for any given initial metric on ${\mathbb{R}}^{2}$ in certain class of metrics, one can always choose suitable initial velocity symmetric tensor such that the solution exists for all time, and the scalar curvature corresponding to the solution metric $g_{ij}$ keeps uniformly bounded for all time. If the initial velocity tensor does not satisfy the condition, then the solution blows up at a finite time, and the scalar curvature $R(t,x)$ goes to positive infinity as $(t,x)$ tends to the blowup points, and a flow with surgery has to be considered. The authors attempt to show that, comparing to Ricci flow, the hyperbolic geometric flow has the following advantage: the surgery technique may be replaced by choosing suitable initial velocity tensor. Some geometric properties of hyperbolic geometric flow on general open and closed Riemann surfaces are also discussed.