Bauer–Fike theorem

The Bauer–Fike theorem is a result in numerical analysis and linear algebra that provides conditions under which the eigenvalues of a perturbed matrix are close to the eigenvalues of the original matrix. Specifically, it addresses how perturbations, particularly in the form of a matrix \( A \) being modified by another matrix \( E \) (where \( E \) typically represents a small perturbation), affect the spectral properties of \( A \).