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. He is known for the Arf invariant of a quadratic form in characteristic 2 (applied in knot theory and surgery theory) in topology, the Hasse–Arf theorem in ramification theory, Arf semigroups, and Arf rings.
Muhammad ibn al Uthaymeen Abu 'Abd Allah Muhammad ibn Saalih ibn Muhammad ibn Sulayman ibn Abd Al Rahman Al Uthaymeen Al Tamimi (Arabic: أبو عبد الله محمد بن صالح بن محمد بن سليمان بن عبد الرحمن العثيمين التميمي) (March 9, 1925 – January 10, 2001) was a Sunni scholar of Saudi Arabia who was considered "a giant within conservative Salafi Islam".