Q: How many mathematicians does it take to screw in a lightbulb?

A: 0.999…

Q: How many mathematicians does it take to screw in a light bulb?

A: None. It’s left to the reader as an exercise.

Q: How many mathematicians does it take to screw in a light bulb?

A: None. A mathematician can’t screw in a light bulb, but he can easily prove the work can be done.

Q: How many mathematicians does it take to screw in a light bulb?

A: Just one, once you’ve managed to present the problem in terms he is familiar with.

Q: How many mathematicians does it take to screw in a light bulb?

A: Three: one to screw it in, and two to figure out how to get rid of the remainder.

Q: How many Californians does it take to replace a lightbulb?

A: Six: one to replace the bulb and five to share in the life experience.

Q: How many mathematicians does it take to screw in a light bulb?

A: One, who gives it to six Californians, thereby reducing it to an earlier riddle.

Q: How many mathematicians does it take to screw in a light bulb?

A: In earlier work, Wiener [1] has shown that one mathematician can change a light bulb. Now, f *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] Weiner, Matthew P,…

Q: How many analysts does it take to screw in a lightbulb?

A: Three. One to prove existence, one to prove uniqueness and one to derive a nonconstructive algorithm to do it.

Q: How many Bourbakists does it take to replace a lightbulb?

A: Changing a lightbulb is a special case of a more general theorem concerning the maintain and repair of an electrical system. To establish upper and lower bounds for the number of personnel required, we must determine whether the sufficient conditions of Lemma 2.1 (Availability of personnel) and those of Corollary 2.3.55 (Motivation of personnel) apply. If these conditions are met, we derive the result by an application of the theorems in Section 3.11.23. The resulting upper bound is, of course, a result in an abstract measure space, in the weak-* topology.

Q: How many classical geometers does it take to replace a lightbulb?

A: None. You can’t do it with a straight edge and a compass.

Q: How many constructivist mathematicians does it take to replace a lightbulb?

A: None. They do not believe in infinitesimal rotations.

Q: How many light bulbs does it take to change a light bulb?

A: One, if it knows its own Godel number.

Q: How many mathematical logicians does it take to replace a lightbulb?

A: None. They can’t do it, but they can prove that it can be done.

Q: How many number theorists does it take to change a light bulb?

A: I don’t know the exact number, but I am sure it must be some rather elegant prime.

Q: How many numerical analysts does it take to replace a lightbulb?

A: 0.9967, after six iterations.

Q: How many simulationists does it take to replace a lightbulb?

A: Infinitly many. Each one builds a fully validated model, but the light actually never goes on.

Q: How many topologists does it take to change a light bulb?

A: It really doesn’t matter, since they’d rather knot.

Q: How many topologists does it take to screw in a lightbulb?

A: Just one. But what will you do with the doughnut?

Q: How many professors does it take to replace a lightbulb?

A: One. With eight research students, two programmers, three post-docs and a secretary to help him.

Q: How many university lecturers does it take to replace a lightbulb?

A: Four. One to do it and three to co-author the paper.

Q: How many graduate students does it take to replace a lightbulb?

A: Only one. But it takes nine years.

Q: How many math department administrators does it take to replace a lightbulb?

A: None. What was wrong with the old one?

Q: How many UC Berkeley students does it take to change a lightbulb?

A: Seventy-six. One to change the lightbulb, fifty to protest the lightbulb’s right not to change, and twenty-five to hold a counter-protest.

Q: How many UC Davis students does it take to change a lightbulb?

A: None. Davis doesn’t have electricity.

Q: How many UC Irvine students does it take to change a lightbulb?

A: None. Irvine looks better in the dark.

Q: How many UC Riverside students does it take to change a lightbulb?

A: None. See UC Irvine.

Q: How many UCLA students does it take to change a lightbulb?

A: One. He just holds the bulb and lets the world revolve around him.

Q: How many UC San Francisco students does it take to change a lightbulb?

A: Two. One to change the lightbulb and one to crack under the pressure.

Q: How many UC San Diego students does it take to change a lightbulb?

A: Two. One to mix the margaritas and one to call the electrician.

Q: How many UC Santa Barbara students does it take to change a lightbulb?

A: Only one, but he gets six credits for it.

Q: How many UC Santa Cruz students does it take to change a lightbulb?

A: Eleven. One to change the lightbulb and ten to share the experience.