English Language & Usage Stack Exchange is a question and answer site for linguists, etymologists, and serious English language enthusiasts. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

There is a lot of statistical criteria/tests (statistics) named after a statistician/mathematician/biologist/economist, etc. But for instance, this and this examples have different spelling...
Do I have to write an apostrophe after a surname in such a situation or not?

share|improve this question
Find what someone else wrote and use that. – Sam Oct 20 '11 at 4:26
Wilcoxon's Signed-Rank Test vs this – stan Oct 20 '11 at 11:29
An interesting case. There is a theorem that is often incorrectly written Stoke's Theorem. It should be Stokes' Theorem or Stokes's Theorem, since the man's name was Stokes. – GEdgar Oct 20 '11 at 14:37
an example – stan Oct 21 '11 at 2:00

There's an interesting discussion on this topic in Wikipedia talk.

Their conclusion:

I guess we just have to live with the fact that some theorems traditionally have apostrophes (Goedel's incompleteness theorem) and other's don't (Tietze extension theorem); it doesn't make sense to have a general rule of style there.

Go with tradition if you can find it, or with whatever manual of style you follow otherwise.

share|improve this answer

It depends on how you refer to it, eg. "Fermat's last theorem" but "the Goldbach conjecture"

share|improve this answer
The Goldbach conjecture is sometimes written as Goldbach's conjecture, but you'd never say, The Fermat's last theorem. (unless you were trying to distinguishing it from your cousin Fermat's theorem. – Sam Oct 20 '11 at 4:18
@Sam - yes if you wrote is as Goldbach's conjecture you would add the apostrophe. It was the first one I could think of that was generally "THE ....." – mgb Oct 20 '11 at 4:20
Doppler effect comes to mind. It would seem strange to say Doppler's effect. Ohm's Law, conversely, would sound funny as The Ohm Law. – Sam Oct 20 '11 at 4:37

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.