Detailed balance for a continuous-time Markov chain (source code)

= Detailed balance for a continuous-time Markov chain

For a <continuous-time Markov chain> with transition rates $q_{ij}$, detailed balance is
$$
\pi_iq_{ij}=\pi_jq_{ji}
$$
for every pair of distinct states. A probability distribution satisfying these equations is an <invariant distribution of a continuous-time Markov chain>, because summing over incoming rates gives $\pi Q=0$. Under the standard nonexplosion assumptions, the equilibrium chain is reversible.