2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42313We shall discuss about some analytic properties of the high-energy parton-parton (and hadron-hadron) scattering amplitudes in gauge theories, when going from Minkowskian to Euclidean theory, and we shall see how they can be related to the still unsolved problem of the s-dependence of the total cross-section.Talk given at the ``26th Johns Hopkins Workshop on current problems in particle theory: high energy reactions'', Heidelberg (Germany), 1-3 August 2002 (JHW2002); 7 pages, LaTeX file. Revised version with two errors in Eqs. (26) and (27) correctedHigh Energy Physics - Phenomenologytext