A generalization of this function provides the foundation of the Lie (“lee”) group–Lie (“lee”) algebra correspondence. This function of negative r over a constant times the Bohr radius appears in the radial equation of the hydrogen atom. The sum of this function of beta times total energy over each microstate comprises (20[1])the canonical (0[3])partition (0[1])function. (0[1])The general (20[1])solution to the time-independent (0[1])(*) Schrödinger equation includes this function’s “complex” form, (0[1])which is also used to represent (10[1])phase factors. The proportion of remaining particles at time t equals this function of t over tau, (0[1])which is a function of half-life, in a model of decay (10[1]0[5])named for this function. (10[1]0[2])For 10 (10[1])points, (0[1])name this function that is the inverse of the natural (10[1])logarithm. (10[12]0[2])■END■ (10[11]0[3])