2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/56470The compatible expansion in series of solutions of both the equations of P-Q pair at neighborhood of the singular point is obtained in closed form for regular and irregular singularities. The conservation laws of the system of ordinary differential equations to arise from the compatibility condition of the P-Q pair are derived.6 pages, LaTeX2eMathematical PhysicsExactly Solvable and Integrable Systemstext