2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/57118The definition of Q-conditional symmetry for one PDE is correctly generalized to a special case of systems of PDEs and involutive families of operators. The notion of equivalence of Q-conditional symmetries under a group of local transformation is introduced. Using this notion, all possible single Q-conditional symmetry operators are classified for the n-dimensional (n >= 2) linear heat equation and for the Euler equations describing the motion of an incompressible ideal fluid.LaTeX2e, 7 pagesMathematical PhysicsAnalysis of PDEsExactly Solvable and Integrable SystemsFluid Dynamics35A30; 58J70; 35K05; 35Q30; 35Q35; 76D05; 76M60text