scholarly journals On the Geometry of the Set of Symmetric Matrices with Repeated Eigenvalues

2018 ◽  
Vol 4 (3-4) ◽  
pp. 423-443 ◽  
Author(s):  
Paul Breiding ◽  
Khazhgali Kozhasov ◽  
Antonio Lerario
Keyword(s):  
Symmetric Matrices ◽  
Repeated Eigenvalues

A new canonical form for complex symmetric matrices

1993 ◽  
Vol 441 (1913) ◽  
pp. 625-640 ◽  
Keyword(s):  
Wave Propagation ◽  
Canonical Form ◽  
Hermitian Matrix ◽  
Symmetric Matrix ◽  
Symmetric Matrices ◽  
Hermitian Matrices ◽  
Repeated Eigenvalues ◽  
Complex Symmetric Matrix ◽  
Complex Symmetric ◽  
Complex Symmetric Matrices

It is well known that every real symmetric matrix, and every (complex) hermitian matrix, is diagonalizable , i. e. orthogonally similar to a diagonal matrix. However, a complex symmetric matrix with repeated eigenvalues may fail to be diagonalizable. We present a block diagonal canonical form, in which each block is quasi-diagonal, to which every complex symmetric matrix is orthogonally similar. As far as applications are concerned, complex symmetric matrices, as opposed to hermitian matrices, play an important role in theories of wave propagation in continuous media (e. g. elasticity, thermoelasticity).

Inverse sensitivity method to self-adjoint systems with repeated eigenvalues

AIAA Journal ◽  
1999 ◽  
Vol 37 ◽  
pp. 933-938
Author(s):  
H. W. Song ◽  
L. F. Chen ◽  
W. L. Wang
Keyword(s):  
Adjoint Systems ◽  
Repeated Eigenvalues ◽  
Sensitivity Method

REMARKS ON THE KIELANOWSKI PARAMETRIZATION OF THE KOBAYASHI-MASKAWA MATRIX

1996 ◽  
Vol 11 (31) ◽  
pp. 2531-2537 ◽  
Author(s):  
TATSUO KOBAYASHI ◽  
ZHI-ZHONG XING
Keyword(s):  
Symmetric Matrices

We study the Kielanowski parametrization of the Kobayashi-Maskawa (KM) matrix V. A new two-angle parametrization is investigated explicitly and compared with the Kielanowski ansatz. Both of them are symmetric matrices and lead to |V13/V23|=0.129. Necessary corrections to the off-diagonal symmetry of V are also discussed.

Asymptotic behavior of repeated eigenvalues of perturbed self-adjoint elliptic operators

2021 ◽  
pp. 1-16
Author(s):  
Alexander Dabrowski
Keyword(s):  
General Type ◽  
Differential Operators ◽  
Laplacian Operator ◽  
Variational Characterization ◽  
Repeated Eigenvalues ◽  
Direct Extension ◽  
Asymptotic Formulae ◽  
Elliptic Differential Operators ◽  
Domain Perturbations ◽  
Boundary Deformation

A variational characterization for the shift of eigenvalues caused by a general type of perturbation is derived for second order self-adjoint elliptic differential operators. This result allows the direct extension of asymptotic formulae from simple eigenvalues to repeated ones. Some examples of particular interest are presented theoretically and numerically for the Laplacian operator for the following domain perturbations: excision of a small hole, local change of conductivity, small boundary deformation.

Converting immanants on skew-symmetric matrices

2021 ◽  
Vol 618 ◽  
pp. 76-96
Author(s):  
M.A. Duffner ◽  
A.E. Guterman ◽  
I.A. Spiridonov
Keyword(s):  
Symmetric Matrices

scholarly journals The location of classified edges due to the change in the geometric multiplicity of an eigenvalue in a tree

2019 ◽  
Vol 7 (1) ◽  
pp. 257-262
Author(s):  
Kenji Toyonaga
Keyword(s):  
Symmetric Matrix ◽  
Symmetric Matrices ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Geometric Multiplicity ◽  
Necessary And Sufficient ◽  
Multiplicity Of An Eigenvalue

Abstract Given a combinatorially symmetric matrix A whose graph is a tree T and its eigenvalues, edges in T can be classified in four categories, based upon the change in geometric multiplicity of a particular eigenvalue, when the edge is removed. We investigate a necessary and sufficient condition for each classification of edges. We have similar results as the case for real symmetric matrices whose graph is a tree. We show that a g-2-Parter edge, a g-Parter edge and a g-downer edge are located separately from each other in a tree, and there is a g-neutral edge between them. Furthermore, we show that the distance between a g-downer edge and a g-2-Parter edge or a g-Parter edge is at least 2 in a tree. Lastly we give a combinatorially symmetric matrix whose graph contains all types of edges.

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