4,639 research outputs found
Coherence in Modal Logic
A variety is said to be coherent if the finitely generated subalgebras of its
finitely presented members are also finitely presented. In a recent paper by
the authors it was shown that coherence forms a key ingredient of the uniform
deductive interpolation property for equational consequence in a variety, and a
general criterion was given for the failure of coherence (and hence uniform
deductive interpolation) in varieties of algebras with a term-definable
semilattice reduct. In this paper, a more general criterion is obtained and
used to prove the failure of coherence and uniform deductive interpolation for
a broad family of modal logics, including K, KT, K4, and S4
Uniform interpolation and coherence
A variety V is said to be coherent if any finitely generated subalgebra of a
finitely presented member of V is finitely presented. It is shown here that V
is coherent if and only if it satisfies a restricted form of uniform deductive
interpolation: that is, any compact congruence on a finitely generated free
algebra of V restricted to a free algebra over a subset of the generators is
again compact. A general criterion is obtained for establishing failures of
coherence, and hence also of uniform deductive interpolation. This criterion is
then used in conjunction with properties of canonical extensions to prove that
coherence and uniform deductive interpolation fail for certain varieties of
Boolean algebras with operators (in particular, algebras of modal logic K and
its standard non-transitive extensions), double-Heyting algebras, residuated
lattices, and lattices
Interpolation in Normal Extensions of the Brouwer Logic
The Craig interpolation property and interpolation property for deducibility are considered for special kind of normal extensions of the Brouwer logic
Failure of interpolation in the intuitionistic logic of constant domains
This paper shows that the interpolation theorem fails in the intuitionistic
logic of constant domains. This result refutes two previously published claims
that the interpolation property holds.Comment: 13 pages, 0 figures. Overlaps with arXiv 1202.1195 removed, the text
thouroughly reworked in terms of notation and style, historical notes as well
as some other minor details adde
Failure of interpolation in the intuitionistic logic of constant domains
This paper shows that the interpolation theorem fails in the intuitionistic
logic of constant domains. This result refutes two previously published claims
that the interpolation property holds.Comment: 13 pages, 0 figures. Overlaps with arXiv 1202.1195 removed, the text
thouroughly reworked in terms of notation and style, historical notes as well
as some other minor details adde
Interpolation in Linear Logic and Related Systems
We prove that there are continuum-many axiomatic extensions of the full
Lambek calculus with exchange that have the deductive interpolation property.
Further, we extend this result to both classical and intuitionistic linear
logic as well as their multiplicative-additive fragments. None of the logics we
exhibit have the Craig interpolation property, but we show that they all enjoy
a guarded form of Craig interpolation. We also exhibit continuum-many axiomatic
extensions of each of these logics without the deductive interpolation
property
A non-classical refinement of the interpolation property for classical propositional logic
We refine the interpolation property of the {^, v, ¬}-fragment of classical propositional logic, showing that if /|= ¬Φ, and /|= Ψ then there is an interpolant Χ constructed using at most atomic formulas occurring in both Φ and Ψ and negation, conjunction and disjunction, such that (i) Φ entails Χ in Kleene’s strong three-valued logic and (ii) Χ entails Ψ in Priest’s Logic of Paradox
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