2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/82009We give a full kinematical classification of all the tree-level two-pion photoproduction processes on the nucleon, which consists of seventeen diagrams. It suggests a method of analysis of two-pion data with little model bias.7 pages, 10 figures (with 96 Dalitz plots)Nuclear Theorytext