Short talk: Motivic cohomology of Carlitz twists

The torsion in the algebraic K-groups of the ring of integers is related to the denominator of Bernoulli numbers. In this short talk we discuss the function field counterpart of this. While there is no known analogue of a function field valued K-theory, one can still define Ext modules among analogues of Tate twists — called Carlitz twists — in an avatar of the category of mixed motives in this context, namely that of Anderson t-motives. We explain how the torsion of those modules are related to Bernoulli-Carlitz numbers. This is joint work with Andreas Maurischat.