The entropy variation due to irreversibility is considered to deduce a principle of stability for open systems. To demonstrate this, thermodynamic Lagrangian and the minimum action principle are used.

The theorem of extremum entropy generation is related to the stochastic order of the paths inside the phase space; indeed, the system evolves, from an indistinguishable configuration to another one, on the most probable path in relation to the paths stochastic order. The result is that, at the...