State Communication

Description:

• $i\leftrightarrow j$ if both states are accessible to each other
• Satisfies:
  1. State $i$ communicates with state $i$, for all $i\ge 0$
  2. If state $i$ communicates with state $j$, then state $j$ communicates with state $i$
  3. Transitive: if state $i$ communicate state $j$, and state $j$ communicates with state $k$, then state $i$ also communicates state $k$