[aebtebeten]

On the abstraction front, I'll confirm that if you go back far enough in just about any line on the Mathematics Genealogy Project, you get to DDs (some Christian, some Islamic).

Example: starting from Frege, we can get from:

https://www.genealogy.math.ndsu.nodak.edu/id.php?id=46166

to

https://www.genealogy.math.ndsu.nodak.edu/id.php?id=125658

and then

https://www.genealogy.math.ndsu.nodak.edu/id.php?id=131444