2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/34553The quantization of gravity coupled to barotropic perfect fluid as matter field and cosmological constant is made and the wave function can be determined for any $κ$ in the FRW minisuperspace model. The meaning of the existence of the classical solution is discussed in the WKB semiclassical approximation9 pages, minor changes, accepted in Int. J. of Theor. PhysGeneral Relativity and Quantum Cosmologytext