scholarly journals Antidiagonals of matrices in a unitary similarity orbit

1994 ◽  
Vol 197-198 ◽  
pp. 317-336 ◽  
Author(s):  
Chi-Kwong Li ◽  
Maria Emília Miranda
Keyword(s):  
Unitary Similarity ◽  
Similarity Orbit

Some Convexity Features Associated with Unitary Orbits

2003 ◽  
Vol 55 (1) ◽  
pp. 91-111 ◽  
Author(s):  
Man-Duen Choi ◽  
Chi-Kwong Li ◽  
Yiu-Tung Poon
Keyword(s):  
Convex Hull ◽  
Linear Space ◽  
Spectral Properties ◽  
Numerical Range ◽  
Symmetric Matrices ◽  
Hermitian Matrices ◽  
Linear Transformations ◽  
Unitary Similarity ◽  
Similarity Orbit ◽  
Real Linear

AbstractLet be the real linear space of n × n complex Hermitian matrices. The unitary (similarity) orbit of C ∈ is the collection of all matrices unitarily similar to C. We characterize those C ∈ such that every matrix in the convex hull of can be written as the average of two matrices in . The result is used to study spectral properties of submatrices of matrices in , the convexity of images of under linear transformations, and some related questions concerning the joint C-numerical range of Hermitian matrices. Analogous results on real symmetric matrices are also discussed.

scholarly journals Preservers of unitary similarity functions on Lie products of matrices

2016 ◽  
Vol 498 ◽  
pp. 160-180 ◽  
Author(s):  
Jianlian Cui ◽  
Chi-Kwong Li ◽  
Yiu-Tung Poon
Keyword(s):  
Unitary Similarity ◽  
Similarity Functions ◽  
Products Of Matrices

Preservers of radial unitary similarity functions on products of operators

2018 ◽  
Vol 542 ◽  
pp. 484-500 ◽  
Author(s):  
M. Bendaoud ◽  
A. Benyouness ◽  
M. Sarih ◽  
S. Sekkat
Keyword(s):  
Unitary Similarity ◽  
Similarity Functions

scholarly journals Unitary similarity to a normal matrix

2012 ◽  
Vol 436 (9) ◽  
pp. 3777-3783 ◽  
Author(s):  
Tatiana G. Gerasimova
Keyword(s):  
Normal Matrix ◽  
Unitary Similarity

scholarly journals Some Theorems On Matrices With Real Quaternion Elements

1955 ◽  
Vol 7 ◽  
pp. 191-201 ◽  
Author(s):  
N. A. Wiegmann
Keyword(s):  
Similarity Transformation ◽  
Elementary Divisor ◽  
Quaternion Matrix ◽  
Unitary Similarity ◽  
Triangular Form ◽  
Quaternion Matrices ◽  
Divisor Theory ◽  
Real Quaternion ◽  
Unitary Similarity Transformation

Matrices with real quaternion elements have been dealt with in earlier papers by Wolf (10) and Lee (4). In the former, an elementary divisor theory was developed for such matrices by using an isomorphism between n×n real quaternion matrices and 2n×2n matrices with complex elements. In the latter, further results were obtained (including, mainly, the transforming of a quaternion matrix into a triangular form under a unitary similarity transformation) by using a different isomorphism.

scholarly journals Unitary automorphisms of the space of Toeplitz-plus-Hankel matrices

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
A.K. Abdikalykov ◽  
V.N. Chugunov ◽  
Kh.D. Ikramov
Keyword(s):  
Toeplitz Matrices ◽  
Hankel Matrices ◽  
Unitary Matrices ◽  
Unitary Similarity

AbstractOur motivation was a paper of 1991 indicating three special unitary matrices that map Hermitian Toeplitz matrices by similarity into real Toeplitz-plus-Hankel matrices. Generalizing this result, we give a complete description of unitary similarity automorphisms of the space of Toeplitz-plus-Hankel matrices.

scholarly journals The closure of the similarity orbit of a Hilbert space operator

1982 ◽  
Vol 6 (3) ◽  
pp. 421-427 ◽  
Author(s):  
Constantin Apostol ◽  
Domingo A. Herrero ◽  
Dan Voiculescu
Keyword(s):  
Hilbert Space ◽  
Space Operator ◽  
Similarity Orbit ◽  
Hilbert Space Operator
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