Thanks, Atvy! Your answered has helped me. I understand now that in both cases there is a theoretical manner to achieve a "no increase" in entropy, but that real-life limitations make it impossible to be realized. I did not want anyway a rigorous argument. It is actually my getting lost in the...
First off, just clarify that I have a very, very superficial knowledge of Physics, so my apologies if my question is based on an obvious misunderstanding of the basic principles underlying the second law of thermodynamics or if it has a rather simple answer.
The doubt that I have is related...