Sorry for the late call …

Sorry for the late call here:

• I did not have time to cover the martingale concept on Wednesday's lecture.
• So in the problem set for Monday: In the note, problem 1.3. (b) and (c), replace "is a martingale" by "has the property that expected change from time 0 to time T is zero". (This is not the martingale property, merely a consequence of it.)