UBC Mathematics Colloquium

Burt Totaro - The torsion index of a complex reductive group

Fri., February 06, 3:00, MATX 1100

We survey the known calculations of the Grothendieck torsion index of a reductive group. The torsion index of G measures the maximum complexity of all G-torsors over all fields. Grothendieck showed that the torsion index is determined by the cohomology ring of the flag manifold G/B. Using this, the torsion index has been computed for all simply connected groups.

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