This paper explores undecidability in theories of positive characteristic function fields in the “geometric” language of rings LF = {0, 1,+, ·, F}, with a unary predicate F for nonconstant elements. We indicate how to generalise existing machinery to prove the undecidability of the ∀1∃+-LF theory (without parameters) of any function field of a curve over an algebraic extension of Fp, not algebraically closed. We discuss the problem (and its geometric implications) further in this context too.
MSC Classification: 03B25 , 12L05