Kelly's lemma states that for a continuous one of these entities, the forward-time stationary distribution and the reverse-time stationary distribution are identical. Kolmogorov's criterion is used to determine whether these 
Kelly's lemma states that for a continuous one of these entities, the forward-time stationary distribution and the reverse-time stationary distribution are identical. Kolmogorov's criterion is used to determine whether these constructs are reversible, and if every sub-component of these entities is aperiodic and positive-recurrent, they are called ergodic. The Metropolis-Hastings algorithm and Gibbs sampling are examples of algorithms that attempt to construct one of these with an equilibrium distribution equal to the (*) sampling probability distribution; those algorithms are named for both Monte Carlo and these entities. A classic example of one of these is the drunkard's walk, in which each end state is absorbing. For 10 points, name these constructs described by a transition matrix, in which the probability of going to any state depends only on the present state.
Kelly's lemma states that for a continuous one of these entities, the forward-time stationary distribution and the reverse-time stationary distribution are identical.