设M为n维完备无边界的流形,它的Ricci曲率有下界-K,这里K为实常数.假设M上的向量场B满足|B|≤γ且△↓B≤K*.这里γ为非负常数,K*为实常数,则带权Laplacjan方程△u+Bu=0任意正的光滑解满足最优梯度估计 |△↓u|^2/u^2≤m(K+K*)+mγ^2/m-n, 其中任意常数m〉n.
Let M be any n-dimensional complete manifold without boundary and with Ricci curvature bounded below by -K, where K is a real constant. If B is a vector field such that the norm |B|≤γ and △↓B≤K* on M, for nonnegative constant γ and real constant K*, then any positive smooth solution of the equation △u+Bu =0 satisfies the following sharp gradient estimate |△↓u|^2/u^2≤m(K+K*)+mγ^2/m-n, on M for any real constant m 〉 n.