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Past Seminars
Thu
09/14/2017
4:00pm
Seminar: Algebra
Linked Fields of Characteristic 2 and their u-Invariant.
Dr. Adam Chapman, Tel-Hai Academic College, Israel.
Contact: Dr. John Duncan, john.duncan@emory.edu
Venue: Mathematics and Science Center, Room W306
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.