Definition:Absorbing State

Definition
Let $\sequence {X_n}_{n \mathop \ge 0}$ be a random walk on a state space $S$.

Let $i \in S$ be an element of the state space $S$.

Then $i$ is an absorbing state of $\sequence {X_n}$ :
 * $X_k = i \implies X_{k + 1} = i$

That is, it is an element of $S$ such that if $\sequence {X_n}$ reaches $i$, it stays there.