Studia Logica最新文献

This work mainly concerns the—here introduced—category of (mathscr {Q})-sets and functional morphisms, where (mathscr {Q}) is a commutative semicartesian quantale. We prove it enjoys all limits and colimits, that it has a classifier for regular subobjects (a sort of truth-values object), which we characterize and give explicitly. Moreover: we prove it to be (kappa )-locally presentable, (where (kappa =max{|mathscr {Q}|^+, aleph _0})); we also describe a hierarchy of monoidal structures in this category.

We employ topos quantum theory as a mathematical framework for quantum logic, combining the strengths of two distinct intuitionistic quantum logics proposed by Döring and Coecke respectively. This results in a novel intuitionistic quantum logic that can capture contextuality, express the physical meaning of superposition phenomenon in quantum systems, and handle both measurement and evolution as dynamic operations. We emphasize that superposition is a relative concept dependent on contextuality. Our intention is to find a model from the perspective of quantum theory that accommodates semantic paradoxes. We refine Aerts et al.’s interpretation of the liar paradox using models from quantum mechanics and present a model based on quantum theory, incorporating contextuality and superposition to interpret semantic paradoxes. We associate the truth values of statements in semantic paradoxes with quantum states in a given context, interpreting statements with unclear truth value assignments as superposition states within the current context. Dynamic operations are employed to distinguish the truth value assignments of statements among different times. Unlike the classic interpretation of paradoxes, we accept the reasonable existence of semantic paradoxes and point out the difference between paradoxes and contradictions.

This is the Editorial Introduction to “S.I.: Strong and Weak Kleene Logics”.

In his seminal paper ‘Truth’, M. Dummett considered negated conditional statements as one of the main motivations for introducing a three-valued logical framework. He left a sketch of an implication connective that, as we observe, shares some intuitions with Wansing-style account for connexivity. In this article, we discuss Dummett’s ‘unfinished’ implication and suggest two possible reconstructions of it. One of them collapses into implication from W. Cooper’s ‘Logic of Ordinary Discourse’ (textbf{OL}) and J. Cantwell’s ‘Logic of Conditional Negation’ (textbf{CN}), whereas the other turns out to be previously unknown implication connective and can be used to obtain a novel logical system, entitled here as (textbf{cRM}_textbf{3}). As to the technical results, we introduce a sound and complete axiomatic proof-system for (textbf{cRM}_textbf{3}) and present a theorem for the semantic embedding of (textbf{CN}) into (textbf{cRM}_textbf{3}).

Communication within groups of agents has been lately the focus of research in dynamic epistemic logic. This paper studies a recently introduced form of partial (more precisely, topic-based) communication. This type of communication allows for modelling scenarios of multi-agent collaboration and negotiation, and it is particularly well-suited for situations in which sharing all information is not feasible/advisable. The paper can be divided into two parts. In the first part, we present results on invariance and complexity of model checking. Moreover, we compare partial communication with the public announcement and arrow update settings in terms of both language-expressivity and update-expressivity. Regarding the former, the three settings are equivalent, their languages being equally expressive. Regarding the latter, all three modes of communication are incomparable in terms of update-expressivity. In the second part, we shift our attention to strategic topic-based communication. We do so by extending the language with a modality that quantifies over the topics the agents can ‘talk about’, thus allowing a form of arbitrary partial communication. For this new framework, we provide a complete axiomatisation, showing also that the new language’s model checking problem is PSPACE-complete. Finally, we argue that, in terms of expressivity, this new language of arbitrary partial communication is incomparable to that of arbitrary public announcements and also to that of arbitrary arrow updates.

Aristotelian diagrams, such as the square of opposition and other, more complex diagrams, have a long history in philosophical logic. Alpha-structures and ladders are two specific kinds of Aristotelian diagrams, which are often studied together because of their close interactions. The present paper builds upon this research line, by reformulating and investigating alpha-structures and ladders in the contemporary setting of logical geometry, a mathematically sophisticated framework for studying Aristotelian diagrams. In particular, this framework allows us to formulate well-defined functions that construct alpha-structures and ladders out of each other. In order to achieve this, we point out the crucial importance of imposing an ordering on the elements in the diagrams involved, and thus formulate all our results in terms of ordered versions of alpha-structures and ladders. These results shed interesting new light on the prospects of developing a systematic classification of Aristotelian diagrams, which is one of the main ongoing research efforts within logical geometry today.

Arising in the study of Quantum Logics, PBZ(^{*})-lattices are the paraorthomodular Brouwer–Zadeh lattices in which the pairs of elements with their Kleene complements satisfy the Strong De Morgan condition with respect to the Brouwer complement. They form a variety (mathbb {PBZL}^{*}) which includes that of orthomodular lattices considered with an extended signature (by endowing them with a Brouwer complement coinciding with their Kleene complement), as well as antiortholattices (whose Brouwer complements are trivial). The former turn out to have directly irreducible lattice reducts and, under distributivity, no nontrivial elements with bounded lattice complements, since the elements with bounded lattice complements coincide to the sharp elements in distributive PBZ(^{*})-lattices. The variety (mathbb {DIST}) of distributive PBZ(^{*})-lattices has an infinite ascending chain of subvarieties, and the variety generated by orthomodular lattices and antiortholattices has an infinity of pairwise disjoint infinite ascending chains of subvarieties.

If we wish to formulate an axiomatic truth-theory interpreting a modal language and treat the symbol of necessity as a sentential operator and not as a quantifier over possible worlds, there arise various problems. These are due partly to the fact that words could have meant something other than what they actually mean and partly to certain principles of modal metaphysics. One of those principles is existentialism about propositions: a proposition that is expressed in a sentence containing a non-empty name could not exist if the referent of the name did not exist. The paper explains how the problems arise. It also explains how we can avoid them using substitutional quantification in the metalanguage. The truth-theory we can construct in that way is compositional and homophonic, and its theorems interpreting the various sentences of the modal language are derived in a straightforward way. The paper develops one such theory for a propositional modal language and one for a first-order modal language. The first-order case involves a number of intricacies that are discussed.

A classical reconstruction of Wright’s first-order logic of strict finitism is presented. Strict finitism is a constructive standpoint of mathematics that is more restrictive than intuitionism. Wright sketched the semantics of said logic in Wright (Realism, Meaning and Truth, chap 4, 2nd edition in 1993. Blackwell Publishers, Oxford, Cambridge, pp.107–75, 1982), in his strict finitistic metatheory. Yamada (J Philos Log. https://doi.org/10.1007/s10992-022-09698-w, 2023) proposed, as its classical reconstruction, a propositional logic of strict finitism under an auxiliary condition that makes the logic correspond with intuitionistic propositional logic. In this paper, we extend the propositional logic to a first-order logic that does not assume the condition. We will provide a sound and complete pair of a Kripke-style semantics and a natural deduction system, and show that if the condition is imposed, then the logic exhibits natural extensions of Yamada (2023)’s results.

A logic family is a bunch of logics that belong together in some way. First-order logic is one of the examples. Logics organized into a structure occur in abstract model theory, institution theory and in algebraic logic. Logic families play a role in adopting methods for investigating sentential logics to first-order like logics. We thoroughly discuss the notion of logic families as defined in the recent Universal Algebraic Logic book.