Who did more ring theory, Cahit Arf or Sind ibn Ali?
Sind ibn Ali He is known to have translated and modified the Zij al-Sindhind. The Zij al-Sindhind was the first astronomical table ever introduced in the Muslim World. As a mathematician Sind ibn ʿAlī was a colleague of al-Khwarizmi and worked closely with Yaqūb ibn Tāriq together they calculated the diameter of the Earth and other astronomical bodies. He also wrote a commentary on "Kitāb al-ğabr wa-l-muqābala" and helped prove the works of al-Khwarizmi. The decimal point notation to the Arabic numerals was introduced by Sind ibn Ali.
Saf ibn Sayyad Saf ibn Sayyad (Arabic: الصف بن الصياد‎ ‎ ), later known as Abdullah ibn Sa'id (Arabic: عبد الله بن سعيد‎ ‎ ), was an alleged claimant of prophethood during the time of Islamic prophet Muhammad and his companions.