. . . "1910-10-11Z"^^ . . "1910Z"^^ . . . . "Arf, Cahit"@en . . . "1997-12-26Z"^^ . "TurkishMathematician" . . "Cahit Arf"@en . "1997Z"^^ . . "Cahit Arf (Turkish: [d\u0361\u0292\u0251hit a\u027Ef]; 11 October 1910 \u2013 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\u2013Arf theorem in ramification theory, Arf semigroups, and Arf rings."@en . . .