Original sentence: Superconductivity is the result of electron correlations
Edited sentence: However there is not exact solution of the Hubbard model in more than one dimension.In them, interactions palys such an important role that qualitatively new phenomena emerge.It also forms the basis for the BCS theory of superconductivity, which is the result of phonon-mediated electron-electron interactions.Its one-dimensional version is considered an archetype of the strong-correlations problem and displays many dramatic manifestations such as quasi-particle fractionalization.Systems that escape a Fermi liquid description are said to be strongly-correlated.This is the case, for example, when the electrons are close to a metal-insulator transition