A Representation Theorem for Second-Order Functionals — mentioned by rssoconnor

Wed, 30 Nov 2022 19:08:27 GMT

Apologies for the jargon, but there isn't room in a comment box for a detailed explanation. "The Essence of the Iterator Pattern"[0] posed an open problem in type theory as to whether or not "lawful traversals", of type `∀ F:Applicative. (X -> F X) -> (B -> F B)` could appear for anything other than what is called a "finitary container"[1], B := ∃S. X^(P S) where the (P S) is a natural number (or equivalently a polynomial functor B := ∃n. C_n * X^n). Or rather, there was an open question as to what laws are needed so that "lawful traversals" would imply that B is a finitary container.…

Paper and discussion history. A mention is not an endorsement.

A Representation Theorem for Second-Order Functionals · HackerPapers discussions

A Representation Theorem for Second-Order Functionals — mentioned by rssoconnor