Teorema de representación de Riesz

The Riesz Representation Theorem states that every continuous linear functional on a Hilbert space can be expressed as an inner product with a fixed element of that space. In simple terms, it means that if you have a way to assign numbers to vectors in a space (a linear functional), there is a specific vector in the space such that applying this functional to any vector is like taking a dot product with that special vector. This creates a direct link between these functionals and vectors, providing a powerful way to understand and work with linear measurements in Hilbert spaces.