Abstract : In this paper,we study compact Riemannian manifolds which Ricci curvature ten-sors are parallel,and establish some pinching theorems for square of length of the Riemanniancurvatuer tensor.

• 摘要 ： 本文研究李奇曲率平行的封闭黎曼流形，证明了黎曼曲率平方的一个拚挤定理。