Probability

Markov Property

Transition probabilities, steady-state convergence and the Markov property in an example discrete-time finite Markov chain

State diagram

step
speed

Steady state $\pi$

Time in state

0 .25 .5 .75 1

Adjust transition probabilities

* Setting a transition probability to 0 removes that edge from the state model

Key ideas

  • Markov property: the next state depends only on the current state, not the path taken to get here.
  • Steady state $\pi_j$: as the walk runs, the fraction of time in each state converges to $\pi_j$, regardless of the starting state.
  • Balance equations: $\pi_j = \sum_k \pi_k \cdot p_{kj}$. The flow into each state equals the flow out.
  • Convergence requires an irreducible (single recurrent class) and aperiodic chain.