- Constructive Mathematical Analysis
- Volume:6 Issue:4
- On the eigenvalue-separation properties of real tridiagonal matrices
On the eigenvalue-separation properties of real tridiagonal matrices
Authors : Yan Wu, Ludwig Kohaupt
Pages : 210-221
Doi:10.33205/cma.1330647
View : 131 | Download : 135
Publication Date : 2023-12-15
Article Type : Research Paper
Abstract :In this paper, we give a simple sufficient condition for the eigenvalue-separation properties of real tridiagonal matrices T. This result is much more than the statement that the pertinent eigenvalues are distinct. Its derivation is based on recurrence formulae satisfied by the polynomials made up by the minors of the characteristic polynomial det(xE-T) that are proven to form a Sturm sequence. This is a new result, and it proves the simple spectrum property of a symmetric tridiagonal matrix studied in Grünbaum\'s paper. Two numerical examples underpin the theoretical findings. The style of the paper is expository in order to address a large readership.Keywords : Characteristic polynomial, Distinct eigenvalues, Eigenvalue separation properties, Minors of determinant, Sturm sequence, Tridiagonal matrix
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