Let M be a compact hypersurface is an(n+1)-dimensional complete constant curvature space N(c),If Ricci curvature of Mis not less than max {0,(n-1)c} and there is a constant main curvature function in M,then M can be classified completly,This is the Liebmann theorem in the widest sense so far.The methods used in this paper can be used to generalize a class of theorems with non-negative (of positive)sectional curvature conditions.
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