4.II.22G
Part II, 2006
Let be a complex Hilbert space. Define what it means for a linear operator to be self-adjoint. State a version of the spectral theorem for compact selfadjoint operators on a Hilbert space. Give an example of a Hilbert space and a compact self-adjoint operator on with infinite dimensional range. Define the notions spectrum, point spectrum, and resolvent set, and describe these in the case of the operator you wrote down. Justify your answers.