Typed first-order logic
From the perspectives of both category theory and computer science, it is natural to extend first-order logic with types. Classical many-sorted first-order logic, where types are sorts with no internal structure, is standard. Surprisingly, it’s difficult to find predicate logics including basic algebraic datatypes (product types and sum types). I’m aware of two major threads in the literature, namely
- Typed lambda calculi with embedded logics
- Curry-Howard correspondence, identifying types with propositions and terms with proofs
but neither is what I want. I’ve even asked for references on MO.
Logical systems
- Z specification language (wiki )
- Typed predicate logic (TPL)
- Property theory with Curry typing (PTCT)
Literature
- Jacobs, 1999: Categorical Logic and Type Theory
- Sec 2.3: Exponents, products, and coproducts
- Sec 2.4: Semantics of simple type theory
- Fiore, Di Cosmo, Balat, 2006: Remarks on isomorphisms in typed lambda calculi
with empty and sum types (doi, pdf)
- Complete proof system for typed lambda calculus with product and sum types
- Categorical semantics: bicartesian closed categories
- Gambino & Aczel, 2006: The generalised type-theoretic interpretation of
constructive set theory (doi, pdf)
- “Logic-enriched type theory”: first-order logic with dependent types