TY - BOOK AU - Deepak,K D TI - Commutant lifting, interpolation and toeplitz operators In several variables U1 - 515.733 23 PY - 2023/// CY - Bangalore PB - Indian Statistical Institute KW - Commutant Lifting Function KW - Hilbert Space N1 - Thesis (Ph.D) - Indian Statistical Institute, 2023; Includes bibliography; Introduction -- Partially isometric toeplitz operators on the polydisc -- Commutant lifting and interpolation on the polydisc -- Perturbations of analytic functions on the polydisc -- Commutant lifting and nevanlinna-pick interpolation on the unit ball; Guided by Prof. Jaydeb Sarkar N2 - The purpose of this thesis is to examine some classical one variable Hilbert function space theoretic results in the context of several complex variables and commuting tuples of bounded linear operators on Hilbert spaces. More specifically, we will be interested in the classical Sarason’s commutant lifting theorem on D, where D = {z ∈ C : |z| < 1}, the open unit disc in C. A significant part of our discussion in this thesis will revolve around the commutant lifting theorem in two different contexts, as well as its following applications of independent importance. Another important object of study will be Toeplitz operators on the polydisc D n , n ≥ 1. It is worth noting that the operator theory, in terms of complexity and known as well as unknown, is different for commuting tuples of contractions and commuting tuples of row contractions, just like the theory of analytic functions differs from the open unit ball to the open unit polydisc. From this perspective, we talk about the commutant lifting theorem in the context of the open unit ball and the polydisc. As we will see in this thesis, the latter scenario seems to be more interesting and challenging UR - http://dspace.isical.ac.in:8080/jspui/handle/10263/7425 ER -