We prove that the extended mean values E(r,s;x,y)E(r,s;x,y) are Schur geometrically convex (or concave, respectively) with respect to (x,y)(0,)×(0,)(x,y)\in(0,\infty)\times(0,\infty) if and only if s+r0s+r\geq 0 (or s+r0s+r\leq 0,respectively).

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Yuming Chu

Dept. of Mathematics, Huzhou Teachers College, Zhejiang, Huzhou 313000, P. R. China

chuyuming@hutc.zj.cn

Xiaoming Zhang

Haining Radio and TV University, Haining 314400, P. R. China

Gendi Wang

Dept. of Mathematics, Huzhou Teachers College, Huzhou 313000, P. R. China

Y. Chu, X. Zhang, G. Wang. “The Schur Geometrical Convexity of the Extended Mean Values.” Journal of Convex Analysis 15 (2008), No. 4, 707–718.