Kac master equation
= Kac master equation
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{title2=$\partial_tF_N=N(Q-I)F_N$}
= Kac's master equation
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{synonym}
The jump process with total collision rate $N$ and normalized pair-angle operator $Q$ evolves by $\partial_tF_N=N(Q-I)F_N$. It preserves mass and the total squared velocity. Its one-coordinate distribution satisfies the <Kac marginal evolution equation>, and its Gaussian <relative entropy in Kac's model> decreases at the rate given by <Kac entropy production>.