Please note this event has an irregular time/location
Speaker:
Oliver Röndigs
Speaker Affiliation:
Universität Osnabrück
https://www.mathematik.uni-osnabrueck.de/index.php?id=1956

October 6, 2022

ESB 4133

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Abstract:

John Milnor's attempt at the higher algebraic K-groups of a field uses the field units as generators and the Steinberg relation as the only relation. The resulting Milnor K-groups map to the higher algebraic K-groups Daniel Quillen defined slightly later as homotopy groups of a certain topological space, and the map is an isomorphism in degrees 0, 1, and 2. A decade later Andrei Suslin constructed a Hurewicz-type homomorphism from Quillen's algebraic K-groups to the Milnor K-groups of a field and proved that the resulting endomorphism
on the n-th Milnor K-group is multiplication by (n-1)! if n>0. He conjectured that the image of the Hurewicz-type homomorphism is the same as the image of this endomorphism (hence as small as possible) and proved the degree 3 case. Recently Aravind Asok, Jean Fasel, and Ben Williams ingeniously used A^1-homotopy groups of algebraic spheres to settle the degree 5 case. Also using A^1-homotopy groups, but now for the projective plane, I will explain how to treat the fourth degree.

Event Topic:

October 6, 2022

3:00pm to 4:00pm

ESB 4133

, , CA

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