May 26th, 2010, 1:06 pm
The test for arbitrage is that at some future point in time you will have a gain for all possible states of the world at that point in time. If there is a chance of a loss (no matter how remote the possibility or small the magnitude) it is not a true arbitrage.Regarding #1, if something is risk free there is no need to discuss expectations -- risk free implies everything is deterministic, nothing is stochastic/random/unknown.Regarding #2, you have an expected return of 80%, but a possible return of something less than 1.5%. So in this case there is no arbitrage, but you have a relative value opportunity.