Importing Logics: Soundness and Completeness Preservation

Importing subsumes several asymmetric ways of combining logics, including modalization and temporalization. A calculus is provided for importing, inheriting the axioms and rules from the given logics and including additional rules for lifting derivations from the imported logic. The calculus is shown to be sound and concretely complete with respect to the semantics of importing as proposed in J. Rasga et al. (100(3):541–581, 2012) Studia Logica.     

Preservation of Craig interpolation by the product of matrix logics

The product of matrix logics, possibly with additional interaction axioms, is shown to preserve a slightly relaxed notion of Craig interpolation. The result is established symbolically, capitalizing on the complete axiomatization of the product of matrix logics provided by their meet-combination. Along the way preservation of the metatheorem of deduction is also proved. The computation of the interpolant in the resulting logic is proved to be polynomially reducible to the computation of the interpolants in the two given logics. Illustrations are provided for classical, intuitionistic and modal propositional logics.     

Importing Logics

The novel notion of importing logics is introduced, subsuming as special cases several kinds of asymmetric combination mechanisms, like temporalization [8, 9], modalization [7] and exogenous enrichment [13, 5, 12, 4, 1]. The graph-theoretic approach proposed in [15] is used, but formulas are identified with irreducible paths in the signature multi-graph instead of equivalence classes of such paths, facilitating proofs involving inductions on formulas. Importing is proved to be strongly conservative. Conservative results follow as corollaries for temporalization, modalization and exogenous enrichment.     

Fibring as Biporting Subsumes Asymmetric Combinations

The transference of preservation results between importing (a logic combination mechanism that subsumes several asymmetrical mechanisms for combining logics like temporalization, modalization and globalization) and unconstrained fibring is investigated. For that purpose, a new (more convenient) formulation of fibring, called biporting, is introduced, and importing is shown to be subsumed by biporting. In consequence, particular cases of importing, like temporalization, modalization and globalization are subsumed by fibring. Capitalizing on these results, the preservation of the finite model property by fibring is transferred to importing and then carried over to globalization.     

Heterogeneous Fibring of Deductive Systems Via Abstract Proof Systems

Fibring is a meta-logical constructor that applied to two logicsproduces a new logic whose formulas allow the mixing of symbols.Homogeneous fibring assumes that the original logics are presentedin the same way (e.g via Hilbert calculi). Heterogeneous fibring,allowing the original logics to have different presentations(e.g. one presented by a Hilbert calculus and the other by asequent calculus), has been an open problem. Herein, consequencesystems are shown to be a good solution for heterogeneous fibringwhen one of the logics is presented in a semantic way and theother by a calculus and also a solution for the heterogeneousfibring of calculi. The new notion of abstract proof systemis shown to provide a better solution to heterogeneous fibringof calculi namely because derivations in the fibring keep theconstructive nature of derivations in the original logics. Preservationof compactness and semi-decidability is investigated.     

Synchronization of Logics

Motivated by applications in software engineering, we propose two forms of combination of logics: synchronization on formulae and synchronization on models. We start by reviewing satisfaction systems, consequence systems, one-step derivation systems and theory spaces, as well as their functorial relationships. We define the synchronization on formulae of two consequence systems and provide a categorial characterization of the construction. For illustration we consider the synchronization of linear temporal logic and equational logic. We define the synchronization on models of two satisfaction systems and provide a categorial characterization of the construction. We illustrate the technique in two cases: linear temporal logic versus equational logic; and linear temporal logic versus branching temporal logic. Finally, we lift the synchronization on formulae to the category of logics over consequences systems.