We present the propositional fragment CLF0 of the Concurrent Logical Framework (CLF). CLF extends the Linear Logical Framework to allow the natural representation of concurrent computations in an object language. The underlying type theory uses monadic types to segregate values from computations. This separation leads to a tractable notion of definitional equality that identifies computations di#ering only in the order of execution of independent steps. From a logical point of view our type theory can be seen as a novel combination of lax logic and dual intuitionistic linear logic. An encoding of a small Petri net exemplifies the representation methodology, which can be summarized as "concurrent computations as monadic expressions ".

When proving a theorem, one makes intermediate claims, leaving parts temporarily unspecified. These `open' parts may be proofs but also terms. In interactive theorem proving systems, one prominently deals with these `unfinished proofs' and `open terms'. We study these `open phenomena' from the point of view of logic. This amounts to finding a correctness criterion for `unfinished proofs' (where some parts may be left open, but the logical steps that have been made are still correct). Furthermore we want to capture the notion of `proof state'. Proof states are the objects that interactive theorem provers operate on and we want to understand them in terms of logic. In this paper we define `open higher order predicate logic', an extension of higher order logic with unfinished (open) proofs and open terms. Then we define a type theoretic variant of this open higher order logic together with a formulas-as-types embedding from open higher order logic to this type theory. We show how this type theory nicely captures the notion of `proof state', which is now a type-theoretic context.

Incomplete logical proofs are the logical counterpart of the incomplete #-terms that one usually works with in an interactive theorem prover based on type theory. In this paper we extend the formalization of such incomplete proofs given in [5] by introducing unknowns that are allowed to provide temporary bindings for variables that are supposed to be bound, but whose binders are not constructed yet - a situation that typically occurs when one does forward reasoning.

different logical foundations

Edinburgh Logical Framework (ELF) (LICS 1987)