TITLE:
On Eigenvalues and Boundary Curvature of the Numerical Rang of Composition Operators on Hardy Space
AUTHORS:
Mohammad Taghi Heydari
KEYWORDS:
Composition Operator, Numerical Range, Eigenvalues, Curvature
JOURNAL NAME:
Advances in Pure Mathematics,
Vol.5 No.6,
May
6,
2015
ABSTRACT:
For a bounded linear operator A on a Hilbert space H, let M(A) be the smallest possible constant in the inequality . Here, p is a point on
the smooth portion of the boundary of the numerical range of A. is the radius of curvature of at this point and is the distance from p to the spectrum of A.
In this paper, we
compute the M(A) for composition operators on Hardy space H2.