"spectral theorem" . "von Neumann spectral theorem" . . "spectral theory" . . "diagonalizable with only real eigenvalues" . "spectral decomposition" . . "Spectral theorem" . . "Von Neumann spectral theorem" . . . . . . . . "Spectral Theorem" . "eigenvalue decomposition" . . "Spectral theorem" . . "spectral measure" . . "spectrum" . . "spectral theorem for compact self-adjoint operators" . "resolvent" . "spectral projection" . .