Hamiltonian Liouville equation (source code)

= Hamiltonian Liouville equation
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{title2=$\partial_tf+\nabla_vH\cdot\nabla_xf-\nabla_xH\cdot\nabla_vf=h$}

= Liouville transport equation
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{synonym}

Transport a phase-space density along <Hamilton's equations>. The <Hamiltonian vector field> is $b=(\nabla_vH,-\nabla_xH)$ and the equation is $\partial_tf+b\cdot\nabla_{x,v}f=h$. Its zero <divergence> gives volume-preserving transport. For $h=0$, the density is constant along characteristics; a source is integrated by the <Duhamel formula for Hamiltonian transport>. This is distinct from the elliptic Liouville equation.