-- How many
mathematicians
-- does it take to screw in a light bulb?
In earlier work, Wiener [1] has shown that one mathematician can
change a light bulb.
If k mathematicians can change a light bulb, and if one more
simply watches them do it, then k+1 mathematicians will have
changed the light bulb.
Therefore, by induction, for all n in the positive integers,
n mathematicians can change a light bulb.
Bibliography:
[1] Wiener, Matthew P., <11485@ucbvax>, "Re: YALBJ", 1986