As a non-native English speaker, I wonder what is the correct way to use the English possessive, also known as Saxon genitive, when dealing with mathematical objects.

It seems to me that there is not an agreement about that, some examples:

Taylor series

Fourier series

Fourier transform

Laplace transform

Euler function

but also...

Cantor's diagonal argument

Euler's totient function

Ramanujan's sum

Kloosterman's sum

D'Alembert's formula

Regarding theorems I think the correct way is:

"AUTHORNAME's theorem"


Thank you in advance for any suggestion.

  • 2
    $\begingroup$ Languages are full of exceptions. (Yours?) I look up the thing in wiki if I want to get the (by definition) correct version $\endgroup$
    – zoli
    Sep 14, 2015 at 15:52
  • 1
    $\begingroup$ @zoli I am Italian. Of course languages are full of exceptions and I would not be surprised if both "Ramanujan's sum" and "Ramanujan sum" were correct form. However, I thought it is better to ask this question instead of looking wikipedia anytime. $\endgroup$
    – user126526
    Sep 14, 2015 at 16:20
  • $\begingroup$ You are getting up votes but not answers : ) (I am Hungarian; the whole Hun is an exception.) $\endgroup$
    – zoli
    Sep 14, 2015 at 18:33
  • $\begingroup$ Here went mine. $\endgroup$
    – zoli
    Sep 14, 2015 at 18:34

1 Answer 1


According to "Writing Mathematical Papers in English" by Jerzy Trzeciak the following are correct:

Minkowski's inequality

the Minkowski inequality.

For theorems he suggests the following two forms:

Fefferman and Stein's famous theorem

the famous Fefferman-Stein theorem.


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