MATH Seminar

Title: Linked Fields of Characteristic 2 and their u-Invariant.
Seminar: Algebra
Speaker: Dr. Adam Chapman of Tel-Hai Academic College, Israel.
Contact: Dr. John Duncan, john.duncan@emory.edu
Date: 2017-09-14 at 4:00PM
Venue: W306
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Abstract: The u-invariant of a field is the maximal dimension of a nonsingular anisotropic quadratic form over that field, whose order in the Witt group of the field is finite. By a classical theorem of Elman and Lam, the u-invariant of a linked field of characteristic different from 2 can be either 0,1,2,4 or 8. The analogous question in the case of characteristic 2 remained open for a long time.. We will discuss the proof of the equivalent statement in characteristic 2, recently obtained in a joint work by Andrew Dolphin and the speaker.