2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/40934The scalar-isoscalar, scalar-isotensor and vector-isovector pion-pion partial wave amplitudes are analyzed. Preliminary results indicate that only the scalar-isoscalar amplitude fitted to the "down-flat" data satisfies Roy's equations and consequently crossing symmetry.3 pages, 2 figures. For the proceedings of MENU 2001, Washington D.C., July 26-31, 2001High Energy Physics - PhenomenologyNuclear Theorytext