 Herbrand's theorem

Herbrand's theorem is an important result in mathematical logic, particularly in the field of model theory and proof theory. It connects syntactic properties of first-order logic formulas to semantic properties of their models. There are several formulations of Herbrand's theorem, but one of the most common versions concerns the existence of models for a set of first-order logic sentences. ### Herbrand's Theorem (Informal Statement) 1.