My Erdös Number is 5.
Erdös numbers have been a part of the folklore of mathematicians throughout the world for many years.
Essentially, the Erdos Number Project studies research collaboration among mathematicians.
If you are curious about your Erdos number, you can compute it.
If you have written a paper with Paul Erdös, you have Erdos Number 1. If you are a coauthor of a coauthor, you have Erdös number 2. And so on.
Here is the mail I receive when I asked to compute my Erdos Number.
Your Erdos number is at most 5, via this path of length 4 to Aguzzoli:
50 #9662 Erdos, P.; Hajnal, A.; Shelah, S. On some general properties of
chromatic numbers. Topics in topology (Proc. Colloq., Keszthely, 1972),
pp. 243–255. Colloq. Math. Soc. Janos Bolyai, Vol. 8, North-Holland,
85i:03125 Makowsky, J. A.; Shelah, S. Positive results in abstract model
theory: a theory of compact logics. Ann. Pure Appl. Logic 25 (1983), no.
819 550 Makowsky, J. A.; Mundici, D. Abstract equivalence relations.
Model-theoretic logics, 717–746, Perspect. Math. Logic, Springer, New
96d:14048 Aguzzoli, Stefano; Mundici, Daniele. An algorithmic
desingularization of $3$-dimensional toric varieties. Tohoku Math. J. (2)
46 (1994), no. 4, 557–572.
S. Aguzzoli, P.Avesani, P.Massa
“Collaborative Case-Based Recommendation Systems”
Lecture Notes in Computer Science, Lecture Notes in Artificial Intelligence
Volume 2416, 2002.