The optimization of a randomness extractor can be best determined from the “min” variant of this variable as the smallest of the Rényi family variants of this variable. For a uniform probability distribution the Hartley function is equivalent to one definition of this variable. A quantum type of this variable vanishes when the density matrix is that of a pure state and is named for (*) Von Neumann. (10[1])The molecular chaos assumption was used to derive an integral equal to a function of this variable, which following later convention was represented with an H. Gibbs created a definition (10[1])of this variable based on a summation of a function of the probability of microstate energies. For 10 points, name this variable equal to the Boltzmann constant times the natural log of microstates. ■END■