Algebraic Geometry Seminar
by Daniel Litt (University of Toronto)
For each (isogeny class of) simple exceptional algebraic group G, Serre asked if there exist motives with Galois group G. We now have a complete answer to this question, due to work of many authors: all exceptional groups do in fact appear. A stronger question is the function field analogue: does there exist a motivic local system with monodromy group G? In this case, the answer was known except in the case G has type E_6. I'll explain joint work with Krämer and Maculan constructing infinitely many essentially distinct motivic local systems with monodromy group E_6.