Kamiński, RobertGarcia-Martin, R.Grynkiewicz, P.Peláez Sagredo, José RamónYndurain, F.J.2023-06-202023-06-202009-01-300217-751X10.1142/S0217751X09043730https://hdl.handle.net/20.500.14352/44850©World Scientific Publishing Company. Conference MESON 2008 (2008. Cracow, Polonia). This work is dedicated to memory of our good friend Prof. F. J. Yndurain, who very unfortunately passed away during the completion of this work. We thank Spanish research contracts PR27/05-13955-BSCH, FPA2004-02602, UCM-CAM 910309 and BFM2003-00856 for partial financial support.We present a set of once subtracted dispersion relations which implement crossing symmetry conditions for the ππ scattering amplitudes below 1 GeV. We compare and discuss the results obtained for the once and twice subtracted dispersion relations, known as Roy’s equations, for three ππ partial JI waves, S0, P and S2. We also show that once subtracted dispersion relations provide a stringent test of crossing and analyticity for ππ partial wave amplitudes, remarkably precise in the 400 to 1.1 GeV region, where the resulting uncertainties are significantly smaller than those coming from standard Roy’s equations, given the same input.engjournal articlehttp://dx.doi.org/10.1142/S0217751X09043730http://www.worldscientific.comhttp://arxiv.org/abs/0809.4766#open access51-73EquationPion-pion amplitudesRoy's equationsFísica-Modelos matemáticosFísica matemática