Arf Invariant

In mathematics, the Arf invariant of a nonsingular quadratic form over a field of characteristic 2 was defined by the Turkish mathematician Cahit Arf, who began the systematic study of quadratic forms over arbitrary fields of characteristic 2. The Arf invariant serves, in characteristic 2, the role the discriminant plays for quadratic forms in other characteristics, and Arf used it, among other tools, in his effort to classify quadratic forms in characteristic 2. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/