dave

Stoke’s theorem. Or generalized Stoke’s theorem. (Both qualify as wrong answers because the apostrophe is in the wrong place; the mathematician’s name is Stokes, not Stoke.)

So there should also be an extra s "Stokes's theorem". Isn't that the rule for a person's name ?

Stokes’ or Stokes’s. either is fine!

Thanks, I used to drop the extra s, but recently an English teacher told me there was one. And now I read that both are actually possible... Don't tell me French is tricky. :-)