Spectral Theory of Discontinuous Functions of Self-adjoint Operators: Essential Spectrum
نویسنده
چکیده
Let H0 and H be self-adjoint operators in a Hilbert space. In the scattering theory framework, we describe the essential spectrum of the difference φ(H)−φ(H0) for piecewise continuous functions φ. This description involves the scattering matrix for the pair H, H0.
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