Sameer Chavan

ON OPERATORS CAUCHY DUAL TO 2-HYPEREXPANSIVE OPERATORS

The operator Cauchy dual to a 2-hyperexpansive operator T , given by T ′ ≡ T (T ∗T )−1, turns out to be a hyponormal contraction. This simple observation leads to a structure theorem for the C∗-algebra generated by a 2-hyperexpansion, and a version of the Berger–Shaw theorem for 2-hyperexpansions. As an application of the hyperexpansivity version of the Berger–Shaw theorem, we show that every analytic 2-hyperexpansive operator with finite-dimensional cokernel is unitarily equivalent to a compact perturbation of a unilateral shift.

An analytic model for left-invertible weighted shifts on directed trees

Let

SPHERICAL TUPLES OF HILBERT SPACE OPERATORS

\mathscr T

Sectorial forms and unbounded subnormals

be a rooted directed tree with finite branching index

ON A FRIEDRICHS EXTENSION RELATED TO UNBOUNDED SUBNORMALS-II

k_{\mathscr T}

Operators Cauchy Dual to 2-Hyperexpansive Operators: The Multivariable Case

and let

Rigidity Theorems for Spherical Hyperexpansions

S_{\lambda} \in B(l^2(V))

Multishifts on directed Cartesian products of rooted directed trees

be a left-invertible weighted shift on

On operators close to isometries

{\mathscr T}

A Moment Problem and Joint q-Isometry Tuples

. We show that