activity
20142026
most citedThe spectral theorem for quaternionic unbounded normal operators based on the S-spectrum

5 citations · 13 across the 14 of their papers we have counts for

collaborators

14 papers

math.CA2026

Orthogonal Polynomials, a Szegő--Verblunsky Theorem and Baxter's Theorem on the Quaternionic Sphere

Connor J. Gauntlett, David P. Kimsey

We introduce a theory of orthogonal polynomials on the unit sphere of the quaternions based on the notion of a -positive measure (which originated in a work of Alpay, Colombo, t…

math.CV2025

Orthogonal Polynomials, Verblunsky Coefficients, and a Szegő-Verblunsky Theorem on the Unit Sphere in

Connor J. Gauntlett, David P. Kimsey

Given a measure on the unit sphere in with Lebesgue decomposition , with respect to the rotation-i…

math.FA2025

A Noncommutative Szegő-Type Theorem on the Row-Ball

Connor J. Gauntlett, David P. Kimsey

In this paper we leverage the recently developed theory of noncommutative (nc) measures to prove a free noncommutative analogue of many known equalities extending the weak Szegő li…

math.FA2023

Moment indeterminateness: the Marcel Riesz variational principle

David P. Kimsey, Mihai Putinar

The discrete data encoded in the power moments of a positive measure, fast decaying at infinity on euclidean space, is incomplete for recovery, leading to the concept of moment ind…

math.FA2021

The spectral theorem for normal operators on a Clifford module

Fabrizio Colombo, David P. Kimsey

In this paper, using the recently discovered notion of the -spectrum, we prove the spectral theorem for a bounded or unbounded normal operator on a Clifford module (i.e., a two-…

math.FA2021

Universality property of the -functional calculus, noncommuting matrix variables and Clifford operators

Fabrizio Colombo, Jonathan Gantner, David P. Kimsey +1

The spectral theory on the -spectrum was born out of the need to give quaternionic quantum mechanics (formulated by Birkhoff and von Neumann) a precise mathematical foundation.…

math.FA2020★ 1 cited

On a minimal solution for the indefinite truncated multidimensional moment problem

David P. Kimsey

We will consider the indefinite truncated multidimensional moment problem. Necessary and sufficient conditions for a given truncated multisequence to have a signed representing mea…

math.FA2019★ 1 cited

The moment problem on curves with bumps

David Kimsey, Mihai Putinar

The power moments of a positive measure on the real line or the circle are characterized by the non-negativity of an infinite matrix, Hankel, respectively Toeplitz, attached to the…

math.SP2015★ 2 cited

Functions of the infinitesimal generator of a strongly continuous quaternionic group

Daniel Alpay, Fabrizio Colombo, Jonathan Gantner +1

The analogue of the Riesz-Dunford functional calculus has been introduced and studied recently as well as the theory of semigroups and groups of linear quaternionic operators. In t…

math.CV2015

Wiener algebra for the quaternions

Daniel Alpay, Fabrizio Colombo, David P. Kimsey +1

We define and study the counterpart of the Wiener algebra in the quaternionic setting, both for the discrete and continuous case. We prove a Wiener-Lévy type theorem and a factoriz…

math.SP2014★ 5 cited

The spectral theorem for quaternionic unbounded normal operators based on the S-spectrum

Daniel Alpay, Fabrizio Colombo, David P. Kimsey

In this paper we prove the spectral theorem for quaternionic unbounded normal operators using the notion of -spectrum. The proof technique consists of first establishing a spect…

math.CV2014

Boundary interpolation for slice hyperholomorphic Schur functions

K. Abu-Ghanem, D. Alpay, F. Colombo +2

A boundary Nevanlinna-Pick interpolation problem is posed and solved in the quaternionic setting. Given nonnegative real numbers , quaternions …

math.SP2014★ 4 cited

The spectral theorem for unitary operators based on the -spectrum

D. Alpay, F. Colombo, D. P. Kimsey +1

The quaternionic spectral theorem has already been considered in the literature, see e.g. [22], [31], [32], however, except for the finite dimensional case in which the notion of s…

math.FA2014

An extension of Herglotz's theorem to the quaternions

D. Alpay, F. Colombo, D. P. Kimsey +1

A classical theorem of Herglotz states that a function from into is positive definite if and only there exists a $\mathbb C^{s\t…