2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/29142We consider a system of non-interacting charged particles moving in two dimensions among fixed hard scatterers, and acted upon by a perpendicular magnetic field. Recollisions between charged particles and scatterers are unavoidable in this case. We derive from the Liouville equation for this system a generalized Boltzmann equation with infinitely long memory, but which still is analytically solvable. This kinetic equation has been earlier written down from intuitive arguments.10 pages RevTeX, 1 Postscript figureCondensed Mattertext