Cahit Arf was born in Selanik(when this city belonged to Ottoman Empire)

in 11 October 1910.He died in Turkey when he was 87.

    Many people know him with 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.

    His academic career started with Istanbul University, and then, Institue for Advanced Study in New Jersey and The University of California in Berkeley followed it. At last, he joined the Middle East Technical University and his studies continued there until his retirement.

    He was the lead of the Turkish Mathematical Society from 1985 to 1989;furthermore, after his death, his collected works were published by this society.

    He was a very talented and well-informed mathematicion.His studies will always have a great importance.He will not be forgotten surely.