content_image/314245.jpg content_image/314247.jpg content_image/314246.jpg content_image/314248.jpg
where 

<img src='content_image/314245.jpg'>

Obviously, 

Furthermore, 

<img src='content_image/314247.jpg'>

<img src='content_image/314246.jpg'>

The canonical 1-stopping time S$_{n}$ takes on only countably many values s$_{i}$ , i ∈ N ; see Ivanoff (1983). Note that for i < j 

<img src='content_image/314248.jpg'>

