Acta mathematica scientia,Series A ›› 2008, Vol. 28 ›› Issue (6): 1173-1180.

• Articles • Previous Articles     Next Articles

Convexity and Geometrical Convexity of the Identic and Logarithmic Means in N Variables

Zheng Ningguo;Zhang Xiaoming;Chu Yuming   

  1. (Department of Mathematics, Huzhou Teachers College, Huzhou 313000)
  • Received:2006-12-09 Revised:2008-03-15 Online:2008-12-25 Published:2008-12-25
  • Contact: Chu Yuming

Abstract:

In this paper, we study the Schur convexity and Schur geometrical convexity
of identric and logarithmic means in n variables. We prove the following results: (1) The identric mean is Schur concave and S-geometrically convex; (2) The first-logarithmic mean is Schur concave; (3) The second-logarithmic mean is Schur convex. At last we give two open problems.

Key words: Convex functions, Schur convex functions, Geometrically convex functions,
Schur geometrically convex functions

CLC Number: 

  • 26D15
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