•CN(G) = {f | G ² f}
•A theory T is a set s.t. CN(T) = T
• T is complete if 8 f either T ² f or T ² : f
•
•If T is finitely axiomatizable and
complete then it is decidable.
•Los-Vaught test: if T has no finite
models and is l-categorical then T is complete