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#### Normal Spectrum of a Subnormal Operator

(2018-03-21)

Let H be a separable Hilbert space over the complex field. The class
S := {N|M : N is normal on H and M is an invariant subspace for Ng of subnormal operators. This notion was introduced by Halmos. The minimal normal ...

#### Dilation Theory of Contractions and Nevanlinna-Pick Interpolation Problem

In this article, we give two different proofs of the existence of the minimal isometric dilation of a single contraction. Then using the existence of a unitary dilation of a contraction, we prove the `von Neumann's ...

#### Operator Theory on Symmetrized Bidisc and Tetrablock-some Explicit Constructions

(2018-07-26)

A pair of commuting bounded operators (S; P ) acting on a Hilbert space, is called a -contraction, if it has the symmetrised bides
= f(z1 + z2; z1z2) : jz1j 1; jz2j 1g C2 as a spectral set. For every -contraction (S; P ), ...

#### Curvature Calculations Of The Operators In Cowen-Douglas Class

(2014-03-03)

In a foundational paper “Operators Possesing an Open Set of Eigenvalues” written several decades ago, Cowen and Douglas showed that an operator T on a Hilbert space ‘H possessing an open set Ω C of eigenvalues determines ...

#### Some Problems in Multivariable Operator Theory

(2017-12-10)

In this thesis we have investigated two diﬀerent types of problems in multivariable operator theory. The ﬁrst one deals with the defect sequence for contractive tuples and maximal con-tractive tuples. These condone deals ...

#### Dilations, Functoinal Model And A Complete Unitary Invariant Of A r-contraction.

(2013-08-02)

A pair of commuting bounded operators (S, P) for which the set
r = {(z 1 +z 2,z 1z 2) : |z 1| ≤1, |z 2| ≤1} C2 is a spectral set, is called a r-contraction in the literature. For a contraction P and a bounded commutant ...