Curve shortening flows on surfaces that are not convex at infinity

TL;DR

This paper investigates the behavior of the curve shortening flow on non-convex at infinity surfaces, showing that curves become graphs after finite time, extending known results beyond convex surfaces.

Contribution

It extends the analysis of curve shortening flow to warped product surfaces that are not convex at infinity, demonstrating finite-time graph formation.

Findings

Curves become graphs after finite time under flow.

Flow behavior similar to convex surfaces despite non-convex at infinity.

Preservation of the graph property during flow.

Abstract

The behavior of the curve shortening flow has been extensively studied. Gage, Hamilton, and Grayson proved that, under the curve shortening flow, an embedded closed curve in the Euclidean plane becomes convex after a finite time and then shrinks to a point while remaining convex. Moreover, Grayson extended these results to surfaces that are convex at infinity and proved results similar to those for plane curves. In this paper, we study the curve shortening flow on surfaces that are not convex at infinity. Specifically, we consider a warped product of a unit circle and an open interval with a strictly increasing warping function. In this setting, we can define a graph property for curves within these warped products. It is known that this graph property is preserved along the curve shortening flow. Similarly to the behavior of the curve shortening flow in the plane, we prove that the curve becomes a graph after a finite time under the curve shortening flow.