[Ads-l] patient zero

[ADSGarson O'Toole]

Dan Goncharoff
> I have always thought about it a 'degrees of separation' from the source.
> The source itself has zero degrees of separation.

Dan: Originally, the explanation you suggest was the one I thought likely.

If you are familiar with Erdos numbers or Bacon numbers then it is
natural to hypothesize that "Patient zero" has the number zero for the
same reason that Kevin Bacon has a Bacon number of zero. A graph is
constructed with links corresponding to "contact" of some kind. For
example, the graph to calculate the Bacon number has a direct link
between two actors iff they have appeared together in a movie. The
graph for the Erdos number has a direct link between two persons iff
they have co-authored a paper together. (Complications ensue when
individuals have co-written a book and not a paper, etcetera.)

The origin node (Erdos or Bacon) is assigned the number zero, and the
other nodes in the graph are labeled with the minimum distance from
the origin node measured by link traversals. Here is an article
stating that Kevin Bacon has a Bacon number 0.

Title: The Six Degrees of Kevin Bacon
Author: Stephanie Blanda
Date: November 22, 2013

http://blogs.ams.org/mathgradblog/2013/11/22/degrees-kevin-bacon/

[Begin excerpt]
While there is only one person with Bacon number 0 (Kevin Bacon
himself), most individuals involved in the Hollywood film industry
have a Bacon number of 6 or less.
[End excerpt]

Does this explain why "patient zero" was assigned the number zero?
Perhaps not. Look at this Wikipedia article that apparently shows the
scientific paper with the graph for "patient zero". The numbers do not
correspond to distance or link traversals:

http://en.wikipedia.org/wiki/Index_case

Garson

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