Boris Adamczewski & Jason Bell

Function fields in positive charcteristic: expansions and Cobham's theorem

In the vein of Christol, Kamae, Mendès France and Rauzy, we consider the analogue of a problem of Mahler for rational functions in positive characteristic. To solve this question, we prove an extension of Cobham's theorem for quasi-automatic functions and use the recent generalization of Christol's theorem obtained by Kedlaya.