In quantum field theory the C-theorem states that there exists a positive real function,
Moreover, at fixed points of the RG flow, which correspond to conformal field theories, Zamolodchikov's C-function is equal to the central charge of the corresponding conformal field theory,[1] which lends the name C to the theorem.
John Cardy in 1988 considered the possibility to generalise C-theorem to higher-dimensional quantum field theory.
However, the problem of finding a proof valid beyond perturbation theory remained open for many years.
In 2011, Zohar Komargodski and Adam Schwimmer of the Weizmann Institute of Science proposed a nonperturbative proof for the A-theorem, which has gained acceptance.