Weakly definable types

L. A. S. Kirby, A. Pillay
1986 Transactions of the American Mathematical Society  
We study some generalizations of the notion of a definable type, first in an abstract setting in terms of ultrafilters on certain Boolean algebras, and then as applied to model theory.
doi:10.1090/s0002-9947-1986-0833696-8 fatcat:c22u3ji4wrepdaov3jvcj3mywa