MEDIUM-ENERGY N-PI-PI-DYNAMICS .1.

New formal apparatus is developed for the dynamics of the Nππ system. The ingredients are the isobar expansion with Bose symmetry, and subenergy unitarity and analyticity. The family of isobar amplitudes considered is substantial in number and realistic for a medium-energy treatment. Dispersion relations are written and the Pasquier inversion procedure is employed, leading to a set of coupled single-variable integral equations. The resulting linear system is suitable for investigating three-body dynamics and for carrying out phenomenological analyses. © 1979 The American Physical Society.