The simplex method is a very efficient algorithm. In this 
talk we see a few of the state-of-the-art theories for explaining this 
observation. We will discuss what it takes for a mathematical model to 
explain an algorithm's qualities, and whether existing theories meet 
this bar. Following this, we will question what the simplex method is 
and if the theoretician's simplex method is the same algorithm as the 
practitioner's simplex method.