11-07. Martingale theory - Optional stopping: the ABRACADABRA problem.

This video gives a proof of one of the most popular examples of application of the optional stopping theorem: How long does it take in average for a monkey to type the word ABRACADABRA? This is Example 5.4 of my Stochastic Modeling book. This video is part of the playlist Advanced Stochastic Processes    • 10-01. Stochastic processes - Filtrations,...  .