2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/148304Model interactions between classical and quantum systems are briefly reviewed. These include: general measurement - like couplings, Stern-Gerlach experiment, model of a counter, quantum Zeno effect, piecewise deterministic Markov processes and meaning of the wave function.17 pages (the revised version: puts a different weight on "meaning of the wave function")High Energy Physics - Theorytext