THE EVOLUTION OF UNPOLARIZED AND POLARIZED STRUCTURE FUNCTIONS AT SMALL X

A survey is given of recent developments on the resummed small-B evolu tion, in a framework based on the renormalization group equation, of n on-singlet and singlet structure functions in both unpolarized and pol arized deep-inelastic scattering. The available resummed anomalous dim ensions are discussed for all these cases, and the most important anal ytic and numerical results are compiled. The quantitative effects of t hese small-a: resummations on the evolution of the various parton dens ities and structure functions are presented, and their present uncerta inties are investigated. An application to QED radiative corrections i s given.