中文摘要：

给出Hamilton和Chow关于二维球面上的Ricci流的一个定理的新证明．这个证明结合了Hamilton关于Ricci流的紧性定理和二维ancientp解的分类和Perelman的非塌缩定理．

英文摘要：

In this short note we give a new proof of a theorem of Hamilton and Chow on the Ricci flow on the 2-sphere. The proof combines Hamilton＇s compactness theorem and his classification of 2- dimensional ancient to-solution of Ricci flow with Perelman＇s no local collapsing theorem.