https://neckpinch.com/authors/ye-zhu/New arXiv papers by Ye Zhu, from Neckpinch Tue, 03 Nov 2026 08:41:12 GMT https://neckpinch.com/papers/2610.29852/arxiv:2610.29852Wed, 21 Oct 2026 00:00:00 GMTWeimin Sheng, Ye Zhu — We give a finite negative-shift criterion for preserving a prescribed exterior noncollapsing bound under fully nonlinear curvature flows whose hypersurfaces need not be convex. The criterion uses the optimized two-point expression of Andrews and Langford. We verify it by a uniform global two-matrix estimate for the explicit speed F_ε(A)= tr A- εfracnormA^(∘)² tr A on the open cone Γ=A∈Sym(n): tr A>0, normA^(∘)< tr A\. Here A^∘ denotes the trace-free part of A. This cone contains the positive cone and also matrices with a negative eigenvalue, while the displayed speed is concave and non-convex. For an explicit range of parameters depending on the initial exterior bound, the cone and that bound are preserved throughout the smooth embedded existence interval. Together with the known interior estimate for concave speeds, this gives two-sided tangent-ball bounds for this nonlinear family, including closed nonconvex initial hypersurfaces.Other curvature flows(Non)collapsingEigenvalues & spectrum https://neckpinch.com/papers/2509.21830/arxiv:2509.21830Fri, 26 Sep 2025 00:00:00 GMTWeimin Sheng, Ye Zhu — We study closed, embedded hypersurfaces in Euclidean space evolving by fully nonlinear curvature flows, whose speed is given by a symmetric, monotone increasing, 1-homogeneous, positive underlying speed function F composed with a modulating function Ψ. Under the assumption that F is convex or inverse-concave and that Ψ satisfies the corresponding structural conditions, we establish exterior noncollapsing estimates for the flow. The main difficulty stems from the nonlinearity of the evolution equation satisfied in the viscosity sense by the exscribed curvature, whereas in previous works it is a solution to the linearized flow. Moreover, in the case where F is inverse-concave, we refine Andrews and Langford's argument for the interior case.Other curvature flows(Non)collapsingHomogeneous spaces