The Green–Kubo relations (Melville S. Green 1954, Ryogo Kubo 1957) give the exact mathematical expression for transport coefficients γ {displaystyle gamma } in terms of integrals of time correlation functions: The Green–Kubo relations (Melville S. Green 1954, Ryogo Kubo 1957) give the exact mathematical expression for transport coefficients γ {displaystyle gamma } in terms of integrals of time correlation functions: