A countable first order theory falls in one of the two classes:
(intractable:) has the maximal number of models in all sufficiently large cardinalities
every model can be decomposed as a tree of countable models
There are some generalizations of this dichotomy beyond first order theories.
Created on May 19, 2015 at 06:21:24. See the history of this page for a list of all contributions to it.