natural deduction metalanguage, practical foundations
type theory (dependent, intensional, observational type theory, homotopy type theory)
computational trinitarianism = propositions as types +programs as proofs +relation type theory/category theory
A geometric theory is of presheaf type if its classifying topos is equivalent to a presheaf topos.
A theory is of presheaf type if and only if its category of models in Set is a finitely accessible category, and if and only if it is sketchable.