In which the below mentioned is about the above mentioned
The Mathematics Genealogy Project is one of those internet curiosities that are worth visiting from time to time. The algorithm is fairly simple.
∀x|x∈M(the set of all doctorates in mathematics)
find x's adviser
For example, take Ludwig's onetime roommate. Boy is widely recognized to be very, very, very smart (Maths Olympiad medalist smart) and his dissertation on the Smoothed Analysis of Gaussian Elimination is of suitably overwhelming obscurity, befitting boy's pedigree. Follow boy's academic ancestry.
One passes through a few generations of unknown (but doubtless worthy) names, until the first tentative signs of recognition occur at Marvin Minsky. After a brief detour into Minsky, we move on.
Somewhere at the turn of the last century, the geography shifts to Europe - sometimes to France, more commonly to Germany. Also, the names start becoming a whole lot more familiar (Klein 1 2, he of bottle fame, for example. Further, see here for a very funny cartoon, one that should join the ranks of the jokes here).
From the mid nineteenth century onwards, the names are all scarily familiar. Scary mostly because you've heard these names in various classes before, and now nothing - nothing - comes back.
Eventually, it is very likely that you will end up at the very obscure (hitherto unheard of, in fact) Herr Erhard Weigel. Why, you ask? How, is it possible, you wonder?
The reason is not hard to seek.
Erhard begat Gottfried
And Gottfried begat Jacob, (en passant, he also begat the calculus)
And Jacob begat Johann (which sounds very odd, because they were in fact siblings)
And Johann begat Leo, and ay there's the rub.
From Euler, it's hoppity-skippity-hop and suddenly we're spitting out the Gods of mathematics. Euler is Lagrange's mai baap and Fourier (of transform fame) and Poisson (of distribution fame) were the apples of Lagrange's eyes.
As the image on the homepage suggests, there's another path through this tree, which leads via Klein to Gauss. Indeed, if the tree/graph were a railway network, Klein would be Mathura.
Go on. Head over to the project, and find out how your mathematics Ph. D. buddy is a descendant of Mencke or Weigel. It's an utterly absorbing pastime, we assure you.