Let A be a closed symmetric operator with deficiency indices n_+ and n_-. Then,
(a) A is self-adjoint if and only if n_+ = n_ = 0.
n_+ (A) = dim[ L_+] and n_- (A) = dim [L_-]
What is this saying? From that, how do I approach this problem?
Thanks for your help,
it is invaluable.