> There's no ADT in category theory. The only place you might find them is in type theory I wouldn't say that this is true. Category theory has a definition of

> There's no ADT in category theory. The only place you might find them is in type theory I wouldn't say that this is true. Category theory has a definition of product of objects, sum/coproduct of objects, terminal object (unit type), and initial object (empty type). There is a correspondence between type and category theory where a certain type theory is the internal language of a certain category: https://ncatlab.org/nlab/show/computational+trinitarianism https://ncatlab.org/nlab/show/computational+trinitarianism Product: https://ncatlab.org/nlab/show/cartesian+product https://ncatlab.org/nlab/show/cartesian+product Coproduct: https://ncatlab.org/nlab/show/coproduct https://ncatlab.org/nlab/show/coproduct Terminal object: https://ncatlab.org/nlab/show/terminal+object https://ncatlab.org/nlab/show/terminal+object Initial object: https://ncatlab.org/nlab/show/initial+object https://ncatlab.org/nlab/show/initial+object