WW ensemble. Suppose we have a closed system, which is a small part of an isolated entity (energy E), volume V0 and number of particles No). The closed system we are looking at is in mechanical interaction with the environment in such a way that its volume can change. We ignore possible energy terms related to the interface (surface energy, surface elasticity, etc.) The environment, whose thermodynamic state is perfectly determined by its energy E2, volume V2 and particle number N2, is approximated as a heat and pressure reserve for the considered system. Determine the probability for the W ofthe considered system with energyei and volume Vi. In this way, also determine the WW partition function M of the system