On the Block Numerical Range of Nonnegative Matrices

Author(s):  
K.-H. Förster ◽  
N. Hartanto
2013 ◽  
Vol 11 (3) ◽  
Author(s):  
Aikaterini Aretaki ◽  
Ioannis Maroulas

AbstractIn this article the rank-k numerical range ∧k (A) of an entrywise nonnegative matrix A is investigated. Extending the notion of elements of maximum modulus in ∧k (A), we examine their location on the complex plane. Further, an application of this theory to ∧k (L(λ)) of a Perron polynomial L(λ) is elaborated via its companion matrix C L.


Author(s):  
R. B. Bapat ◽  
T. E. S. Raghavan
Keyword(s):  

Filomat ◽  
2017 ◽  
Vol 31 (19) ◽  
pp. 6005-6013
Author(s):  
Mahdi Iranmanesh ◽  
Fatemeh Soleimany

In this paper we use the concept of numerical range to characterize best approximation points in closed convex subsets of B(H): Finally by using this method we give also a useful characterization of best approximation in closed convex subsets of a C*-algebra A.


2021 ◽  
Vol 624 ◽  
pp. 1-13
Author(s):  
Kennett L. Dela Rosa ◽  
Hugo J. Woerdeman
Keyword(s):  

2021 ◽  
Vol 88 (1) ◽  
Author(s):  
Antoine Gautier ◽  
Matthias Hein ◽  
Francesco Tudisco

AbstractWe analyze the global convergence of the power iterates for the computation of a general mixed-subordinate matrix norm. We prove a new global convergence theorem for a class of entrywise nonnegative matrices that generalizes and improves a well-known results for mixed-subordinate $$\ell ^p$$ ℓ p matrix norms. In particular, exploiting the Birkoff–Hopf contraction ratio of nonnegative matrices, we obtain novel and explicit global convergence guarantees for a range of matrix norms whose computation has been recently proven to be NP-hard in the general case, including the case of mixed-subordinate norms induced by the vector norms made by the sum of different $$\ell ^p$$ ℓ p -norms of subsets of entries.


Positivity ◽  
2021 ◽  
Author(s):  
Abdellatif Bourhim ◽  
Mohamed Mabrouk
Keyword(s):  

Author(s):  
Abderrahim Baghdad ◽  
Chraibi Kaadoud Mohamed
Keyword(s):  

2021 ◽  
Vol 10 (1) ◽  
pp. 1-8
Author(s):  
Christian Grussler ◽  
Anders Rantzer

Abstract We address the issue of establishing standard forms for nonnegative and Metzler matrices by considering their similarity to nonnegative and Metzler Hessenberg matrices. It is shown that for dimensions n 3, there always exists a subset of nonnegative matrices that are not similar to a nonnegative Hessenberg form, which in case of n = 3 also provides a complete characterization of all such matrices. For Metzler matrices, we further establish that they are similar to Metzler Hessenberg matrices if n 4. In particular, this provides the first standard form for controllable third order continuous-time positive systems via a positive controller-Hessenberg form. Finally, we present an example which illustrates why this result is not easily transferred to discrete-time positive systems. While many of our supplementary results are proven in general, it remains an open question if Metzler matrices of dimensions n 5 remain similar to Metzler Hessenberg matrices.


1977 ◽  
Vol 21 (2) ◽  
pp. 365-373 ◽  
Author(s):  
C. K. Chui ◽  
P. W. Smith ◽  
R. R. Smith ◽  
J. D. Ward
Keyword(s):  

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