How to spell Erdős in HTML

Yoshio Okamoto

I happen to visit many webpages writing something about Paul Erdős, a great Hungarian mathematician. However, most of them misspell Erdős as Erdös. (For example, the famous Erdős number project page uses ö when this article was first written (Oct 23, 2004).)

Notice the difference of "ő" and "ö" which might be difficult for those who do not know Hungarian. (Actually I don't know Hungarian, so I made this mistake until quite recently.)

Here is a way to type them.

ő ö
HTML ő ö
LaTeX \H{o} \"{o}

I guess there are two main reasons why many webpages make this mistake.

  1. Hungarian is not that popular. So people just don't know the difference of "ő" and "ö." On the other hand, German is much more popular. So most people know, at least, the existence of the character ö. Actually I know even many research papers spell Erdős' name with ö, not with ő.
  2. The character ő is not on the list of characters in the HTML specification supplied by W3C. So, even if people know the letter ő, they might find it impossible to show in their HTML documents. However, since the specification follows the character set defined in ISO 10646 and this set is equivalent to Unicode, we can find "ő" as one of the entries in "Latin-1 Extended-A" in Unicode Codechart. There, the codes are given in the hexadecimal way, and ő is encoded as "0151." So we can alternatively use ő to show "ő." (Note that hexadecimal 0151 is decimal 337.)
I hope this page reduces the number of appearances of "Erdös" and increase "Erdős" in the world.


Tibor Szabó told me the difference of ö and ő. Ingo Schurr told me the use of Unicode. Günter Rote found a typo.

Comments are welcome. My email address is below.

Last modified:Fri Feb 3 2012