Landau and Pomeranchuk tried to justify the possibility (c) in the case of QED and theory. They have noted that the growth of in Eq.1 drives the observable charge to the constant limit, which does not depend on . The same behavior can be obtained from the functional integrals, omitting the quadratic terms in the action. If neglecting the quadratic terms is valid already for , it is all the more valid for of the order or greater than unity: it gives a reason to consider Eq.1 to be valid for arbitrary . Validity of these considerations at the quantitative level is excluded by the non-quadratic form of the -function.