What if Your PhD Advisor for Your Second PhD Was Also Your PhD Student

Life in academia is never dull and the surprises continue.

A few weeks ago, I was asked to be on the doctoral dissertation committee of a student at the Royal Institute of Technology (KTH) in Stockholm, Sweden. For logistical reasons -- the defense was to take place on June 1 in Stockholm and since my apartment in Gothenburg was not yet confirmed I declined (although I very much wanted to be on this committee).

In the meantime, my wonderful hosts at the School of Business, Economics and Law at the University of Gothenburg found me a wonderful apartment in which I will be staying for the month of June.

The "student" who was defending his doctoral dissertation, and, I might add, successfully passed it, was PO Lindberg, who already has a PhD, which he received in 1975.  PO even achieved  the rank of Full Professor. He is well-known in operations research and mathematical programming circles and has been a friend since I received my PhD.

Those of you who are reading this post closely, must now be impressed that someone, who already has a PhD, got a second PhD and 37 years after his first! His second PhD is in Transportation Science.

However, that is not the full story.

PO´s former doctoral student, Lars-Goran Mattsson, was his dissertation advisor for his second PhD!

As PO stated in the acknowledgments in his dissertation, what will this do to his mathematics genealogy tree!

In academic genealogy and the academic family tree,  the son (Lars-Goran Mattsson) of his father (PO Lindberg) is now his father´s father.