Title of article :
Betterment for estimates of the numerical radii of Hilbert space operators
Author/Authors :
Davarpanah ، Mohammad Department of Mathematics - Islamic Azad University, Ferdows Branch , Moradi ، Hamid Reza Department of Mathematics - Payame Noor University (PNU)
Abstract :
We give several inequalities involving numerical radii ω (·) and the usual operator norm k·k of Hilbert space operators. These inequalities lead to a considerable improvement in the well-known inequalities 1/2 ||T|| ≤ ω (T) ≤ ||T|| .
Keywords :
Numerical radius , Usual operator norm , Inequality , Contraction operator
Journal title :
AUT Journal of Mathematics and Computing
Journal title :
AUT Journal of Mathematics and Computing
