Shelah 1971-90: classify first-order theories by # of models in each cardinality. Stable/superstable/ω-stable. Strongly-minimal/uncountably-categorical (Morley). Foundation of geometric model theory.
Shelah 1971-90: classify first-order theories by # of models in each cardinality. Stable/superstable/ω-stable. Strongly-minimal/uncountably-categorical (Morley). Foundation of geometric model theory.