My apologies for having to leave on such short notice. Unfortunately, some worsening health issues gave me no choice. What made it especially difficult was having to stop teaching the many talented and dedicated students I was fortunate to work with in all of my classes.
You are attending an outstanding school and there are numerous highly-qualified faculty, some perhaps more so than the writer of this note, available to continue the courses from here.
I wish each of you the very best.