摘要
Let M be a complete Riemannian manifold, A be its Laplacian, ▽ be the gradient operator. The Riesz transform ▽（-△）<sup>-1/2</sup> was introduced first by R. S. Stritrartz, and earlier on, E. M. Stein had introduced Riesz transform on Lie groups. Stritrartz proved
