Title of article :
Reverses of the first Hermite-Hadamard type inequality for the square operator modulus in Hilbert spaces
Author/Authors :
Dragomir ، S. S. College of Engineering Science - Victoria University
Abstract :
Let (H;⟨⋅,⋅⟩) be a complex Hilbert space. Denote by B(H) B(H) the Banach C^∗ -algebra of bounded linear operators on H . For A∈B(H) we define the modulus of A by |A|:=(A∗A)1/2 and \ funcReA:=12(A∗+A). . In this paper we show among other that, if A, B∈B(H) with 0≤m≤|(1−t)A+tB|^2≤M for all t∈[0,1], then 0≤∫1_0f(|(1−t)A+tB|2)dt−f(|A|2+\funcRe(B∗A)+|B|23)≤2[f(m)+f(M)2−f(m+M2)]1H for operator convex functions f:[0,∞)→R . Applications for power and logarithmic functions are also provided
Keywords :
Operator convex functions , Hermite , Hadamard inequality , midpoint inequality , operator power and logarithmic functions
Journal title :
Journal of Linear and Topological Algebra
Journal title :
Journal of Linear and Topological Algebra