Modified mean curvature flow of graphs in Riemannian manifolds
Jocel Faustino Norberto de Oliveira, Jorge Herbert Soares de Lira, Matheus Nunes Soares
TL;DR
This work studies the long-time existence of smooth Killing graphs evolving by a modified mean curvature flow in warped product manifolds \\bar{M} = M \\times_\\varrho \\mathbb{R} with a nonvanishing Killing field X. The flow is recast as a quasilinear parabolic PDE for a graph function u on M, with \\partial_t u = \\mathcal{Q}[u] and W = (\\varrho^{-2} + | abla^M u|^2)^{1/2}, linking the geometric evolution to the variational problem of the constrained area functional \\mathcal{A}_\\sigma[u]. The authors establish robust a priori estimates—height, gradient, and curvature—via Hessian comparison, barrier constructions, and Simons-type identities, under natural curvature and warping assumptions. These estimates yield local existence on geodesic balls and, through an exhaustion argument, a global, smooth, longtime solution for locally Lipschitz initial Killing graphs when the parameter \\sigma satisfies a sharp upper bound. The results extend earlier Euclidean and hyperbolic cases to a general warped-product setting, providing a unified framework for modified mean curvature flow of Killing graphs with strong regularity and existence guarantees.
Abstract
We obtain height, gradient, and curvature a priori estimates for a modified mean curvature flow in Riemannian manifolds endowed with a Killing vector field. As a consequence, we prove the existence of smooth, entire, longtime solutions for this extrinsic flow with smooth initial data.
