ABSTRACT
In this chapter we consider those normed spaces where, as in the case of the Euclidean space Rn , there is an inner product which is connected with the norm by a simple relation: The square of the norm of an element is the inner product of that element with itself. Some examples to keep in mind are, of course, Rn and Cn , and what we will have the occasion to verify is a universal model of a Hilbert space, L 2(μ)
