Article
A Normal Variation of the Horn Problem: The Rank 1 Case
Annals of Functional Analysis
Document Type
Article
Publication Date
10-1-2014
Keywords
- The problem of A. Horn,
- Normal matrices,
- Upper Hessenberg
Disciplines
Abstract
Given three n-tuples {λi}ni=1, {μi}ni=1, {vi}ni=1 of complex numbers, we introduce the problem of when there exists a pair of normal matrices A and B such that σ(A) = {λi}ni=1, σ(B) = {μi}ni=1, and σ(A+B) = {vi}ni=1, where σ(.) denote that spectrum. In the case when λk = 0, k = 2,...,n, we provide necessary and sufficient conditions for the existence of A and B. In addition, we show that the solution pair (A,B) is unique up to unitary similarity. The necessary and sufficient conditions reduce to the classical A. Horn inequalities when n-tuples are real.
Additional Comments
NSF grant #: DMS-0901628
ORCID ID
0000-0001-7613-7191
ResearcherID
G-7341-2019
Citation Information
Lei Cao and Hugo J. Woerdeman. "A Normal Variation of the Horn Problem: The Rank 1 Case" Annals of Functional Analysis Vol. 5 Iss. 2 (2014) p. 138 - 146 ISSN: 2008-8752 Available at: http://works.bepress.com/lei-cao/4/
©2014 Duke University Press