Who did more ring theory, Cahit Arf or Sind ibn Ali?
Cahit Arf: Cahit Arf (] ; 11 October 1910 – 26 December 1997) was a Turkish mathematician. Sind ibn Ali:  He also wrote a commentary on "Kitāb al-ğabr wa-l-muqābala" and helped prove the works of al-Khwarizmi. Sind ibn Ali:  The decimal point notation to the Arabic numerals was introduced by Sind ibn Ali.
i don't know