Abstract. This paper presents a formalization of Nuprl's metatheory in Coq. It includes a nominal-style definition of the Nuprl language, its reduction rules, a coinductive computational equivalence, and a Currystyle type system where a type is defined as a Partial Equivalence Relation (PER) à la Allen. This type system includes Martin-Löf dependent types, a hierarchy of universes, inductive types and partial types. We then prove that the typehood rules of Nuprl are valid w.r.t. this PER semantics and hence reduce Nuprl's consistency to Coq's consistency.
In a large development, Nuprl's metatheory has been formalized in Coq REF .
Towards a Formally Verified Proof Assistant
ITP
Computer Science