English

Deforming a hypersurface by principal radii of curvature and support function

Analysis of PDEs 2025-06-30 v1

Abstract

We study the motion of smooth, closed, strictly convex hypersurfaces in Rn+1\mathbb{R}^{n+1} expanding in the direction of their normal vector field with speed depending on the kkth elementary symmetric polynomial of the principal radii of curvature σk\sigma_k and support function hh. A homothetic self-similar solution to the flow that we will consider in this paper, if exists, is a solution of the well-known LpL_p-Christoffel-Minkowski problem φh1pσk=c\varphi h^{1-p}\sigma_k=c. Here φ\varphi is a preassigned positive smooth function defined on the unit sphere, and cc is a positive constant. For 1kn1,pk+11\leq k\leq n-1, p\geq k+1, assuming the spherical hessian of φ1p+k1\varphi^{\frac{1}{p+k-1}} is positive definite, we prove the CC^{\infty} convergence of the normalized flow to a homothetic self-similar solution. One of the highlights of our arguments is that we do not need the constant rank theorem/deformation lemma of Guan-Ma and thus we give a partial answer to a question raised in Guan-Xia. Moreover, for k=n,pn+1k=n, p\geq n+1, we prove the CC^{\infty} convergence of the normalized flow to a homothetic self-similar solution without imposing any further condition on φ.\varphi. In the final section of the paper, for 1k<n1\leq k<n, we will give an example that spherical hessian of φ1p+k1\varphi^{\frac{1}{p+k-1}} is negative definite at some point and the solution to the flow loses its smoothness.

Keywords

Cite

@article{arxiv.1803.08470,
  title  = {Deforming a hypersurface by principal radii of curvature and support function},
  author = {Mohammad N. Ivaki},
  journal= {arXiv preprint arXiv:1803.08470},
  year   = {2025}
}