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This paper concerns a commutant lifting theorem and a Nevanlinna-Pick type interpolation result in the setting of multipliers from vector-valued Drury-Arveson space to a large class of vector-valued reproducing kernel Hilbert spaces over…

Functional Analysis · Mathematics 2019-12-04 Deepak K. D. , Deepak Pradhan , Jaydeb Sarkar , Dan Timotin

In this paper we obtain a multivariable commutator lifting inequality, which extends to several variables a recent result of Foias, Frazho, and Kaashoek. The inequality yields a multivariable lifting theorem generalizing the noncommutative…

Functional Analysis · Mathematics 2007-05-23 Gelu Popescu

In this article we study commutant lifting, more generally intertwining lifting, for different reproducing kernel Hilbert spaces over two domains in $\mathbb{C}^n$, namely the unit ball and the unit polydisc. The reproducing kernel Hilbert…

Functional Analysis · Mathematics 2020-04-07 Sibaprasad Barik , Monojit Bhattacharjee , B. Krishna Das

We give necessary and sufficient conditions for solving the spectral Nevanlinna--Pick lifting problem. This reduces the spectral Nevanlinna--Pick problem to a jet interpolation problem into the symmetrized polydisc.

Complex Variables · Mathematics 2015-10-14 Rafael B. Andrist

The article deals with isometric dilation and commutant lifting for a class of $n$-tuples $(n \geq 3)$ of commuting contractions. We show that operator tuples in the class dilate to tuples of commuting isometries of BCL type. As a…

Functional Analysis · Mathematics 2025-08-08 B. Krishna Das , Samir Panja

Our two principle goals are generalizations of the commutant lifting theorem and the Nevanlinna-Pick interpolation theorem to the context of Hardy algebras built from $W^*$-correspondences endowed with a sequence of weights. These theorems…

Operator Algebras · Mathematics 2016-08-18 Jennifer R Good

It is very elementary to observe that functions interpolating an extremal two-point Pick problem on the polydisc are just left inverses to complex geodesics. In the present article we show that the same property holds for a three-point Pick…

Complex Variables · Mathematics 2015-03-12 Lukasz Kosinski

We solve the commutant lifting and interpolation problems in the setting of the Hardy space and Schur functions on the open unit ball of $\mathbb{C}^n$. Our solutions also signify the role of inner functions on the unit ball, objects whose…

Complex Variables · Mathematics 2025-12-15 Jaydeep Bhattacharjee , Deepak K. D. , Jaydeb Sarkar

In this paper we obtain a noncommutative multivariable analogue of the classical Nevanlinna-Pick interpolation problem for analytic functions with positive real parts on the open unit disc. As consequences, we deduce some results concerning…

Functional Analysis · Mathematics 2009-02-04 Gelu Popescu

An indefinite generalization of Nudel'man's problem is used in a systematic approach to interpolation theorems for generalized Schur and Nevanlinna functions with interior and boundary data. Besides results on existence criteria for…

Functional Analysis · Mathematics 2007-05-23 D. Alpay , T. Constantinescu , A. Dijksma , J. Rovnyak

This paper presents a few additions to commutant lifting theory. An operator interpolation problem is introduced and shown to be equivalent to the relaxed commutant lifting problem. Using this connection a description of all solutions of…

Functional Analysis · Mathematics 2007-05-23 A. E. Frazho , S. ter Horst , M. A. Kaashoek

We introduce a "dual-space approach" to mixed Nevanlinna-Pick/Carath\'eodory-Schur interpolation in Banach spaces X of holomorphic functions on the disk. Our approach can be viewed as complementary to the well-known commutant lifting…

Functional Analysis · Mathematics 2020-07-16 Oleg Szehr , Rachid Zarouf

Recent results of Davidson-Paulsen-Raghupathi-Singh give necessary and sufficient conditions for the existence of a solution to the Nevanlinna-Pick interpolation problem on the unit disk with the additional restriction that the interpolant…

Functional Analysis · Mathematics 2020-03-02 J. A. Ball , V. Bolotnikov , S. ter Horst

We give a characterization for the existence of a holomorphic interpolant on the unit polydisc $\mathbb{D}^n,$ $n\geq 2,$ for prescribed three-point Pick--Nevanlinna data. One of the key steps is a characterization for the existence of an…

Complex Variables · Mathematics 2020-09-08 Vikramjeet Singh Chandel

There are three new things in this paper about the open symmetrized bidisk $\mathbb G = \{(z_1+z_2, z_1z_2) : |z_1|, |z_2| < 1\}$. They are motivated in the Introduction. In this Abstract, we mention them in the order in which they will be…

Functional Analysis · Mathematics 2017-12-05 Tirthankar Bhattacharyya , Haripada Sau

In this article, we establish a connection between Pick bodies and invariant functions. We demonstrate that an invariant function can be associated with any Pick body, which determines the solvability of a given Pick interpolation problem…

Complex Variables · Mathematics 2025-02-17 Anindya Biswas

Two different problems are considered here. First, a characterization of sampling sequences for the class of analytic functions from the disc into itself is given. Second, a version of Schwarz-Pick Lemma for $n$ points leads to an…

Complex Variables · Mathematics 2023-08-03 Nacho Monreal Galan , Michael Papadimitrakis

This paper studies the determining sets for analytic functions from the symmetrized bidisk into the open unit disk in $\mathbb C$. It relates the idea to the uniqueness of the solutions of a Nevanlinna-Pick interpolation problem. It also…

Complex Variables · Mathematics 2022-08-15 B. Krishna Das , P. Kumar , H. Sau

Two different problems are considered here. First, a version of Schwarz-Pick Lemma for $n$ points leads to an interpolation problem for analytic functions from the disc into itself, which may be considered as a particular case of the…

Classical Analysis and ODEs · Mathematics 2014-07-30 Nacho Monreal Galan , Michael Papadimitrakis

When is the collection of $\mathsf S$-Toeplitz operators with respect to a tuple of commuting bounded operators $\mathsf S= (S_1, S_2, \ldots , S_{d-1}, P)$, which has the symmetrized polydisc as a spectral set, non-trivial? The answer is…

Functional Analysis · Mathematics 2022-07-05 Tirthankar Bhattacharyya , B. Krishna Das , Haripada Sau
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