Zhifei Zhu

activity

20242026

collaborators

5 papers

math.AP2026

Sharp endpoint multilinear estimates for oscillatory integrals and spectral clusters

Shengwen Gan, Cheng Zhang, Zhifei Zhu

We prove sharp $k$ -linear $L^{p}$ estimates for Carleson--Sjölin oscillatory integral operators with arbitrary separated frequency scales for all $k \geq 2$ and $1 \leq p \leq \infty$ . The…

math.AP2026

Restriction estimates for toral eigenfunctions and lattice points in spherical regions

Cheng Zhang, Zhifei Zhu

We establish new $L^{2}$ restriction estimates for toral eigenfunctions. These estimates are sharp in certain cases, and thus prove a conjecture of Huang-Zhang for smooth submanifold…

math.CA2026

Maximal growth of the Stein-Wainger oscillatory integral

Cheng Zhang, Zhifei Zhu

We establish a precise hierarchy for the maximal growth of the Stein-Wainger oscillatory integral as the regularity of the phase varies over Denjoy-Carleman classes, such as the Ge…

math.DG2025

Homological Filling and Minimal Varifolds in Four-Dimensional Einstein Manifolds

Wenjie Fu, Zhifei Zhu

We study the smallest area $A (M, g)$ of a 2-dimensional stationary integral varifold in a closed Einstein 4-manifold $(M^{4}, g)$ with $Ric_g = λg, |λ|\leq 3, Vol(M,g)\geq v>0, diam(M,…

math.DG2024

Length of closed geodesics on Riemannian manifolds with good covers

Zhifei Zhu

In this article, we prove a generalization of our previous result in [12]. In particular, we show that for an $n$ -dimensional, simply connected Riemannian manifold with diameter $D…