Erdős–Bacon number

A person's Erdős–Bacon number is the sum of one's Erdős number—which measures the "collaborative distance" in authoring academic papers between that person and Hungarian mathematician Paul Erdős—and one's Bacon number—which represents the number of links, through roles in films, by which the individual is separated from American actor Kevin Bacon. The lower the number, the closer a person is to Erdős and Bacon, which reflects a small world phenomenon in academia and entertainment.

In general, to have a defined Erdős–Bacon number, it is a necessary (but not a sufficient) condition for one to have both appeared in a film and co-authored an academic paper. It is not sufficient because it may still be impossible to reach Erdős through one's academic coauthors or Bacon through one's film co-appearances.

Astronomer Carl Sagan has an Erdős number of no more than 4 via Steven J. Ostro and a Bacon number of 2, for a total of 6. Physicist Richard Feynman has an Erdős number of 3 and a Bacon number of 3, having appeared in the film Anti-Clock alongside Tony Tang.

Geneticist Jonathan Pritchard appeared in the 1998 movie Without Limits which gives him a Bacon Number of 2. Pritchard has an Erdős Number of 4 thus giving him an Erdős–Bacon Number of 6.

Theoretical physicist Stephen Hawking has an Erdős–Bacon number of 6: His Bacon number of 2 (via his appearance alongside John Cleese in Monty Python Live (Mostly) who acted alongside Kevin Bacon in The Big Picture) is lower than his Erdős number of 4.

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