2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/47226The QCD treatment of the photon structure is recalled. Emphasis is given to the recently derived momentum sum rule, and to the proper choice of the factorization scheme and/or boundary conditions for the evolution equations beyond the leading order. Parametrizations of the photon's parton content are examined and compared. The small-x behaviour of the photon structure is briefly discussed.14 pages LaTeX, including 6 eps-figures. Invited talk presented at PHOTON '97, Egmond aan Zee, The Netherlands, May 1997. To appear in the proceedingsHigh Energy Physics - Phenomenologytext