+**Liouville's Theorem** (sometimes Liouville's conservation theorem) is a fundamental principle in [Classical Mechanics](/wiki/classical_mechanics) and statistical physics. It states that the density of points representing an ensemble of identical systems in [phase space](/wiki/phase_space) remains constant along the trajectories of the systems. This elegant conservation law implies that the phase-space volume occupied by such an ensemble is invariant over time.
+## See also
+- [Hamiltonian Mechanics](/wiki/hamiltonian_mechanics)
+- [Statistical Mechanics](/wiki/statistical_mechanics)
+- [Ergodicity](/wiki/ergodicity)
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