When $R=0$ all rates vanish. Every state is absorbing and \b[the communicating classes are the $s$ singletons], all closed. There are no open communicating classes. Every <probability> distribution is stationary in this degenerate case.

Solution

Past exam of the mathematics course of the University of Cambridge / 2007 / ii / Paper 2 / 26J / b / Solution

 Solution (source code)