The BBGKY hierarchy consists of distribution functions, named after Bogolyubov, Born, Green, Kirkwood and Yvon. The BBGKY hierarchy is a system of equations for the dynamical behavior of fluids, with the important extension to dense liquids. The equations are exact, and relate the phase space probability density for n+1 particles to the phase space probability density for n particles . In Ref. 2 it is shown that the H-theorem follows from the Kirkwood superposition approximation.
- M. Born and H. S. Green "A General Kinetic Theory of Liquids. I. The Molecular Distribution Functions", Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences 188 pp. 10-18 (1946)
- H. S. Green "A General Kinetic Theory of Liquids. II Equilibrium Properties", Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences 189 pp. 103-117 (1947)