Hernández U., J. E., & Zeballos M., T. (2018). Characterization of Hilbert’s separable spaces. Visión Antataura, 2(1), 41–53. Retrieved from https://revistas.up.ac.pa/index.php/antataura/article/view/178
In this paper separable Hilbert spaces of infinite dimension are characterized, and it is proven that they are isometrically isomorphic to the Hilbert space l2 .