Perturbation Theory for Linear Operators

Kato's perturbation theory underwrites the small-mutation expansion in dalla2026between, giving the analytic first-order correction to the dominant Perron eigenvector around the unperturbed diagonal fitness block and yielding the epsilon-scaling formula for off-optimum mass within the dominant class.

Referenced in riva2026intensity as the foundation for operator perturbation theory, supporting the claim that singular values of the bound heat operator vary continuously with smooth changes in the intensity.