A Cheng-Yau type estimate for positive biharmonic functions

Guosheng Jiang, Mingxiang Li, Zhehui Wang

We establish a Cheng-Yau type estimate for positive biharmonic functions on complete Riemannian manifolds with Ricci curvature satisfies $Ri{c}_g\ge -(n-1)Kg$. If $u$ is a positive…