2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/206398Contrary to wide-spread opinion that the final state interaction (FSI) enlarges the amplitude $<2π;I=0|K^0>$, we argue that FSI is not able to increase the absolute value of this amplitude.10 pages, minor correctionsHigh Energy Physics - Phenomenologytext