Statistical Mechanics/The Foundations/The Postulates

The Three famous Postulates of Thermodynamics. There exists a function called the entropy of extensive parameters of any system, defined for all stabilized states having the property that the entropy maximizes. The entropy of a composite system is additive over constituent subsystems. As a function, it's also continuous, differentiable, and monotically increasing with respect to energy. If (∂u/∂S)V,N=0, then S=0 The only other thing of note is notice in Postulate Two: (The Entropy is a) monotonically increasing with respect to energy. in other words: ∂S/∂U > 0 1/T > 0 Temperature can never be negative.