2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/47658A recent criticism raised by M.R.Pennington on our pipi-production amplitudes seems to be due to his misunderstanding on our description, and is not right. Essential point of the relation between our scattering and production amplitudes is, in connection to the unitarity and the final state interaction theorem, briefly explained.4 pages, TeX, uses ptptex.styHigh Energy Physics - Phenomenologytext