There are at least three equations named after Boltzmann. The first is the famous
where S is the entropy, k is Boltzmann's constant, and W is the number of states accessible to the system. Boltzmann first wrote down his equation in 1872, although Planck was actually the first to write it in this form. This equation is inscribed on Boltzmann's tomb.
Liouville's Equation, Vlasov Equation
References
Chamberlain, J. W. and Hunten, D. M. Theory of Planetary Atmospheres: An Introduction to Their Physics and Chemistry, 2nd ed. San Diego, CA: Academic Press, pp. 358-360, 1987.
