activity
20142025
most citedMajorization and a Schur-Horn Theorem for positive compact operators, the nonzero kernel case

23 citations · 69 across the 15 of their papers we have counts for

collaborators

15 papers

math.OA2025

The continuous functional calculus in Lean

Anatole Dedecker, Jireh Loreaux

The continuous functional calculus is perhaps the most fundamental construction in the theory of operator algebras, especially -algebras. Here we document our formalization…

math.OA2022

k1-injectivity of the Paschke dual algebra for certain simple C*-algebras

Jireh Loreaux, P. W. Ng, Arindam Sutradhar

Let be a nonunital separable simple stable C*-algebra with strict comparison of positive elements and having finite extreme boundary, and let $\mathc…

math.FA2022★ 1 cited

On commutators of compact operators via block tridiagonalization: generalizations and limitations of Anderson's approach

Jireh Loreaux, Sasmita Patnaik, Srdjan Petrovic +1

We offer a new perspective and some advances on the 1971 Pearcy--Topping problem: Is every compact operator a commutator of compact operators? Our goal is to analyze and generalize…

math.FA2021

Closedness of the orbit-closed -numerical range and submajorization

Jireh Loreaux, Sasmita Patnaik

For a positive trace-class operator and a bounded operator , we provide an explicit description of the closure of the orbit-closed -numerical range of in terms of tho…

math.OA2021

-injectivity of the Paschke dual algebra, and uniqueness

Jireh Loreaux, P. W. Ng, Arindam Sutradhar

We prove that a large class of Paschke dual algebras of simple unital C*-algebras are -injective. As a consequence, we obtain interesting -uniqueness theorems which genera…

math.FA2021

Matrix splitting and ideals in

Jireh Loreaux, Gary Weiss

We investigate the relationship between ideal membership of an operator and its pieces relative to several canonical types of partitions of the entries of its matrix representation…

math.FA2020

Convexity of the orbit-closed -numerical range and majorization

Jireh Loreaux, Sasmita Patnaik

We introduce and investigate the orbit-closed -numerical range, a natural modification of the -numerical range of an operator introduced for trace-class by Dirr and vom E…

math.FA2019★ 1 cited

On diagonals of operators: selfadjoint, normal and other classes

Jireh Loreaux, Gary Weiss

We provide a survey of the current state of the study of diagonals of operators, especially selfadjoint operators. In addition, we provide a few new results made possible by recent…

math.OA2019★ 5 cited

Remarks on Essential Codimension

Jireh Loreaux, Ping W. Ng

We look for generalizations of the Brown-Douglas-Fillmore essential codimension result, leading to interesting local uniqueness theorems in -theory. We also study the structure…

math.FA2017

Traces on ideals and the commutator property

Jireh Loreaux, Gary Weiss

We propose a new class of traces motivated by a trace/trace class property discovered by Laurie, Nordgren, Radjavi and Rosenthal concerning products of operators outside the trace…

math.OA2017★ 6 cited

Restricted diagonalization of finite spectrum normal operators and a theorem of Arveson

Jireh Loreaux

Kadison characterized the diagonals of projections and observed the presence of an integer. Arveson later recognized this integer as a Fredholm index obstruction applicable to any…

math.OA2016★ 13 cited

Kadison's Pythagorean Theorem and essential codimension

Victor Kaftal, Jireh Loreaux

Kadison's Pythagorean theorem (2002) provides a characterization of the diagonals of projections with a subtle integrality condition. Arveson (2007), Kaftal, Ng, Zhang (2009), and…

math.FA2016★ 10 cited

Thompson's theorem for compact operators and diagonals of unitary operators

John Jasper, Jireh Loreaux, Gary Weiss

As applications of Kadison's Pythageorean and carpenter's theorems, the Schur-Horn theorem, and Thompson's theorem, we obtain an extension of Thompsons theorem to compact operators…

math.FA2014★ 10 cited

Diagonality and idempotents with applications to problems in operator theory and frame theory

Jireh Loreaux, Gary Weiss

We prove that a nonzero idempotent is zero-diagonal if and only if it is not a Hilbert-Schmidt perturbation of a projection, along with other useful equivalences. Zero-diagonal ope…

math.FA2014★ 23 cited

Majorization and a Schur-Horn Theorem for positive compact operators, the nonzero kernel case

Jireh Loreaux, Gary Weiss

Schur-Horn theorems focus on determining the diagonal sequences obtainable for an operator under all possible basis changes, formally described as the range of the canonical condit…