Update markov_chains_II.md

Author: longye-tian

lectures/markov_chains_II.md

@@ -183,6 +183,7 @@ distribution, then, for all $x \in S$,
 Here
 
 * $\{X_t\}$ is a Markov chain with stochastic matrix $P$ and initial distribution $\psi_0$
+
 * $\mathbf{1} \{X_t = x\} = 1$ if $X_t = x$ and zero otherwise.
 
 The result in [theorem 4.3](llnfmc0) is sometimes called **ergodicity**.