Example of Birth/Death Process---II

• It is also easy to do---the seemingly harder problem---of a finite number of telephone lines in exchange.

• There is an example of this sort in problem set about parking lots.

• Similar techniques can be used to decide on a number of servicemen needed to repair a set of machines of prescribed reliability. Here,

  Death = machine starts working

  Birth = machine breaks down, and

  machine's broken.

  There is a beautiful discussion of this on pages 416--420 of Feller.