ON A THEOREM OF J.T. LEWIS
关于J.T.Lewis的一个定理

This note points out that the sufficiency half of the characterization theoremfor best L_1 approximation with interpolatory constraints given by J. T. Lewis~1,Theorem5.3]is not valid. Our theorem 1 gives a general characterization theorem, whence if anadditional condition is assumed, then our theorem 2 will give a complete statement ofLewis' theorem.