Created by Knut M. Synstadfrom the Noun Project

Detailed Balance

Definition (Detailed balance)

A transition matrix PP and a pmf π\pi are said to be in detailed balance if πipij=πjpji, \mboxforalli,jS\pi_{i}p_{ij}=\pi_{j}p_{ji}, \ \mbox{for all }i,j\in S

Theorem (Sufficient Condition for Identifying Invariant Distribution)

If PP and π\pi are in detailed balance, then π\pi is invariant in PP.

Remark

To find an invariant distribution, we could try to solve λipij=λjpji\mboxforalli,jS\lambda_{i}p_{ij}=\lambda_{j}p_{ji}\mbox{ for all }i,j\in S

Remark

Detailed balance is a sufficient condition for identifying invariant distribution, not a necessary one. Hence, there may be an invariant distribution but detailed balance does not guarantee finding it.

Definition (Detailed balance — continuous)

A Q-Matrix QQ and a distribution π\pi are said to be in detailed balance if πiqij=πjqji\pi_{i}q_{ij}=\pi_{j}q_{ji}for all i,jIi,j\in I.

Theorem

If QQ and π\pi are in detailed balance then πQ=0\pi Q = 0.

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