3 papers
math.FA2014
Some operator convex functions of several variables
Zhihua Zhang
We obtain operator concavity (convexity) of some functions of two or three variables by using perspectives of regular operator mappings of one or several variables. As an applicati…
math.MG2010
On Edwards-Child's inequality
Yudong Wu, Zhihua Zhang, Zhigang Wang
In this paper, by making use of one of Chen's theorems and the method of mathematical analysis, we refine Edwards-Child's inequality and solve a conjecture posed by Liu.
math.MG2010
On the circumradius of a special class of n-simplices
Yudong Wu, Zhihua Zhang
An n-simplex is called circumscriptible (or edge-incentric) if there is a sphere tangent to all its n(n + 1)/2 edges. We obtain a closed formula for the radius of the circumscribed…