Question

When a sequence form a hilbert space orthonormal basis?

Answer 1

Answer:us

Step-by-step explanation:

Answer 2

In the end, the main reason for using only Hilbert spaces in quantum theory is technical. What is ultimately observable in experiment is a spectral measure corresponding to an "observable", i.e., a self-adjoint operator in some Hilbert space and a "state," i.e., an element of that Hilbert space.