We investigate model theoretic characterisations of the expressive power of modal logics in terms of bisimulation invariance. The paradigmatic result of this kind is van Benthem’s theorem, which says that a first-order formula is invariant under bisimulation if, and only if, it is equivalent to a formula of basic modal logic. The present investigation primarily concerns ramifications for specific classes of structures. We study in particular model classes defined through conditions on the underlying frames, with a focus on frame classes (...) that play a major role in modal correspondence theory and often correspond to typical application domains of modal logics. Classical model theoretic arguments do not apply to many of the most interesting classes–for instance, rooted frames, finite rooted frames, finite transitive frames, well-founded transitive frames, finite equivalence frames–as these are not elementary. Instead we develop and extend the game-based analysis over such classes and provide bisimulation preserving model constructions within these classes. Over most of the classes considered, we obtain finite model theory analogues of the classically expected characterisations, with new proofs also for the classical setting. The class of transitive frames is a notable exception, with a marked difference between the classical and the finite model theory of bisimulation invariant first-order properties. Over the class of all finite transitive frames in particular, we find that monadic second-order logic is no more expressive than first-order as far as bisimulation invariant properties are concerned — though both are more expressive here than basic modal logic. We obtain ramifications of the de Jongh–Sambin theorem and a new and specific analogue of the Janin–Walukiewicz characterisation of bisimulation invariant monadic second-order for finite transitive frames. (shrink)

Recently, some authors – call them Reformists – have argued that the traditional Presentism-Eternalism and Actualism-Possibilism debates in the metaphysics of time and modality respectively are unclear or insubstantial, and should therefore give way to the newer Temporaryism-Permanentism and Contingentism- Necessitism debates. In ‘On characterising the presentism/eternalism and actualism/possibilism debates’ (2016, Analytic Philosophy 57: 110-140), Ross Cameron defends the Conservative position that the traditional debates are both substantial and distinct from the Temporaryism-Permanentism and Contingentism- Necessitism debates. In this paper I (...) provide a Reformist response to Cameron’s arguments. (shrink)

A characterisation of a type of weak-operator continuous linear functional on certain linear subsets of B, where H is a Hilbert space, is derived within Bishop-style constructive mathematics.

The characterisation of normal stem cells and cancer stem cells uses the same paradigm. These cells are isolated by a fluorescence‐activated cell sorting step and their stemness is assayed following implantation into animals. However, differences exist between these two kinds of stem cells. Therefore, the translation of the experimental procedures used for normal stem cell isolation into the research field of cancer stem cells is a potential source of artefacts. In addition, normal stem cell therapy has the objective of (...) regenerating a tissue, while cancer stem cell‐centred therapy seeks the destruction of the cancer tissue. Taking these differences into account is critical for anticipating problems that might arise in cancer stem cell‐centred therapy and for upgrading the cancer stem cell paradigm accordingly. (shrink)

We use nonstandard methods, based on iterated hyperextensions, to develop applications to Ramsey theory of the theory of monads of ultrafilters. This is performed by studying in detail arbitrary tensor products of ultrafilters, as well as by characterising their combinatorial properties by means of their monads. This extends to arbitrary sets and properties methods previously used to study partition regular Diophantine equations on. Several applications are described by means of multiple examples.

We study probabilistic characterisation of a random model of a finite set of first order axioms. Given a set of first order axioms.

Description Logics (DLs) are a family of formal knowledge representation formalisms and the most well-known formalisms in semantics-based systems. The central focus of this research is on logical-terminological characterisation/analysis of possibilistic and probabilistic descriptions of events in DLs. Based on a logical characterisation of the concept of `being', this paper conceptualises events within DLs world descriptions. Accordingly, it deals with the concepts of `possibility of events' and `probability of events'. The main goal of this research is to investigate (...) how possible and probable notations can, terminologically and logically, be interpreted and analysed within DLs world descriptions. In other words, the research logically-terminologically investigates how possibilistic and probabilistic descriptions of events can be expressed in DLs. (shrink)

We describe the role of morphosyntactic categories and syntactic dependencies in the process of semantically interpreting composite expressions. Special attention will be paid to the combinatorial properties conveyed by morphosyntactic categories such as nominals and verbs, as well as by syntactic dependencies like subject, direct object, or nominal modification. The semantic characterisation of these grammatical structures is based on cognitive abilities and abstract conceptualisations. This will provide us with theoretical arguments to review and extend some basic assumptions of Cognitive (...) Grammar and related work. (shrink)

We extend the earlier results on the equivalence between the Boolean and the multivalued dependencies in relational databases and fragments of the Boolean propositional logic. It is shown that these equivalences are still valid for the databases that store complex data elements obtained from the recursive nesting of record, list, set and multiset constructors. The major proof argument utilises properties of Brouwerian algebras.The equivalences have several consequences. Firstly, they provide new insights into databases that are not in first normal form. (...) Secondly, they characterise the implication of data dependencies in nested databases in purely logical terms. The database designer can take advantage of these equivalences to reduce database design problems to well-studied problems in Boolean propositional logic. Furthermore, relational database design solutions can be reused to solve problems for nested databases. (shrink)

We identify bar recursion on moduli of continuity as a fundamental notion of constructive mathematics. We show that continuous functions from the Baire space \ to the natural numbers \ which have moduli of continuity with bar recursors are exactly those functions induced by Brouwer operations. The connection between Brouwer operations and bar induction allows us to formulate several continuity principles on the Baire space stated in terms of bar recursion on continuous moduli which naturally characterise some variants of bar (...) induction. These principles state that a certain kind of continuous function from \ to \ admits a modulus of continuity with a bar recursor. The results for the Baire space are recast in the setting of the Cantor space \ using the notion of fan recursor, a bar recursor for binary trees. This yields characterisations of uniformly continuous functions on the Cantor space and fan theorem in terms of fan recursors. The results for the Cantor space hold over the extensional version of intuitionistic arithmetic in all finite types ), and those for the Baire space hold over \ extended with the type for Brouwer operations. Our work places Spector’s bar recursion in a proper context of Brouwer’s intuitionistic mathematics and clarifies the connection between bar recursion and bar induction. (shrink)

This essay is an attempt to point up the gap between, on the one hand, the methods currently available to the biologist in the laboratory and, on the other, the kind of data that he or she would need in order to characterise genetically engineered proteins of topical biological interest in such a way as to make use of the techniques of protein engineering.

Given Conciliar Christology and a compositionalist metaphysics of the incarnation, I explore whether ‘qua-propositions’ are capable of solving the coherence problem in Christology. I do this by probing the metaphysical aspect of qua-propositions, since ‘semantics presupposes metaphysics’. My proposal focuses on the fact that the Word accidentally owns an individual human nature. Due to that individuality, the human properties first characterise the individual human nature and, in a ‘next step’, this individual human nature characterises the Word. I call this ‘stepped (...) characterisation’. Subsequently, I show that stepped characterisation validates the use of qua-propositions in Conciliar Christology. Hence, qua-propositions are not merely ‘muddling the waters of logic’. (shrink)

Irrespective of the short academic history of Christian spirituality, a vast number of academic and popular publications ensued and is still dynamically growing. Many definitions have been proposed to define (Christian) spirituality. Spirituality is also no longer connected only to religion, although in this research the focus will fall on Christian spirituality. This research intends to partake in the continuing academic dialogue to define Christian spirituality. Christian spirituality is interpreted from the perspective of the divine-human conversation. This research consists of (...) three sections. In the first section, a working definition of Christian spirituality is formulated. In the second section, various aspects that constitute spiritualities are distinguished and discussed. In the last section, the constituents of Christian spirituality are pointed out and are reviewed from a conversational perspective. The focus will be on ‘the experience of the divine’ when living a life that resonates with the Christian life. (shrink)

We describe the role of morphosyntactic categories and syntactic dependencies in the process of semantically interpreting composite expressions. Special attention will be paid to the combinatorial properties conveyed by morphosyntactic categories such as nominals and verbs, as well as by syntactic dependencies like subject, direct object, or nominal modification. The semantic characterisation of these grammatical structures is based on cognitive abilities and abstract conceptualisations. This will provide us with theoretical arguments to review and extend some basic assumptions of Cognitive (...) Grammar and related work. (shrink)

Context is essential in virtually all human activities. Yet some logical notions seem to be context-free. For example, the nature of the universal quantifier, the very meaning of “all”, seems to be independent of the context. At the same time, there are many quantifier expressions, and some are context-independent, while others are not. Similarly, purely logical consequence seems to be context-independent. Yet often we encounter strong inferences, good enough for practical purposes, but not valid. The two types of examples suggest (...) a general problem: how to characterise the context-free logical concepts in their natural environment, that is, in the field of their context-dependent associates. A general Thesis on Quantifiers is formulated: among all quantifiers, the context-free ones are just those definable by the universal quantifier. The issue of inferences is treated following the approach introduced by Richard L. Epstein: valid ones are an extreme case, the result of the disappearance of context-dependence. This idea can be applied to an analysis of a form of abduction, called “reductive inference” in Polish literature on logic. A tentative Thesis on Inferences identifies the validity of a strong inference that is context-independent. (shrink)

Background: The traditional approach to resolving ethics concerns may not address underlying organisational issues involved in the evolution of these concerns. This represents a missed opportunity to improve quality of care “upstream”. The purpose of this study was to understand better which organisational issues may contribute to ethics concerns. Methods: Directed content analysis was used to review ethics consultation notes from an academic children’s hospital from 1996 to 2006 (N = 71). The analysis utilised 18 categories of organisational issues derived (...) and modified from published quality improvement protocols. Results: Organisational issues were identified in 68 of the 71 (96%) ethics consult notes across a range of patient settings and reasons for consultation. Thirteen of the 18 categories of organisational issues were identified and there was a median of two organisational issues per consult note. The most frequently identified organisational issues were informal organisational culture (eg, collective practices and approaches to situations with ethical dimensions that are not guided by policy), policies and procedures (eg, staff knows policy and/or procedural guidelines for an ethical concern but do not follow it) and communication (eg, communication about critical information, orders, or hand-offs repeatedly does not occur among services). Conclusions: Organisational issues contribute to ethical concerns that result in clinical ethics consults. Identifying and addressing organisational issues such as informal culture and communication may help decrease the recurrence of future similar ethics concerns. (shrink)

Thomas appears four times within the narrative framework of the Fourth Gospel. His presence in the Gospel introduces some of the strategic transitions within the macro-narrative structure. The following are some of the crucial moments that are introduced through the entry of Thomas: firstly, Thomas' character is brought to the foreground towards the end of Jesus' public ministry, where a transition is underway through Lazarus' death and raising to Jesus' death and resurrection ; secondly, he appears as a significant interlocutor (...) engaged in dialogue so that Jesus' identity as 'the way, the truth, and the life' may be revealed to the disciples during his private ministry ; thirdly, Thomas' character appears towards the climax of the Book of Glory as he is instrumental in revealing the identity of Jesus as 'Lord' and 'God' ; and fourthly, he appears as one of the seven disciples during the post-resurrection context in Galilee. The unique placement of Thomas communicates something significant about the character and his development within the narrative. (shrink)

In Béziau a logic \ was defined with the help of the modal logic \. In it, the negation operator is understood as meaning ‘it is not necessary that’. The strong soundness–completeness result for \ with respect to a version of Kripke semantics was also given there. Following the formulation of \ we can talk about \-like logics or Beziau-style logics if we consider other modal logics instead of \—such a possibility has been mentioned in [1]. The correspondence result between (...) modal logics and respective Beziau-style logics has been generalised for the case of normal logics naturally leading to soundness–completeness results [see Marcos :279–300, 2005) and Mruczek-Nasieniewska and Nasieniewski :229–248, 2005)]. In Mruczek-Nasieniewska and Nasieniewski :185–196, 2008), :189–203, 2009) some partial results for non-normal cases are given. In the present paper we try to give similar but more general correspondence results for the non-normal-worlds case. To achieve this aim we have to enrich original Beziau’s language with an additional negation operator understood as ‘it is necessary that not’. (shrink)

Accuracy-first epistemologists argue that rational agents have probabilistically coherent credences. But why should we care, given that we can’t help being incoherent? A common answer: probabilistic coherence is an ideal to be approximated as best one can. De Bona (in: Philos Sci 84(2), 189–213, 2017) and Staffel (in: Unsettled thoughts: a theory of degrees of rationality, Oxford University Press, 2019) show how accuracy-firsters can spell out this answer by adopting an appropriate notion of approximate coherence. In this essay, I argue (...) that De Bona and Staffel’s proposal is not entirely satisfactory, because it does not show whether, or why, it’s generally better to be more rather than less approximately coherent from an accuracy-first perspective. To address this point, I give a characterisation of their notion of approximate coherence in terms of accuracy. This shows that accuracy-firsters should maintain that more approximately coherent credences are better than less approximately coherent ones _if and only if_ they accept that it’s better to miss out on less rather than more guaranteed accuracy. (shrink)

Plato's Sophist is complex. Its themes are many and ambiguous. The early grammarians gave it the subtitle1tEp1. 'tau ov'to~ ('on being') and assigned it to Plato's logical investigations. The Neoplatonists prized it for a theory of ontological categories they preferred to Aristotle's. Modern scholars sometimes court paradox and refer to the Sophist as Plato's dialogue on not-being (because the question ofthe possibility of not-being occupies much of the dialogue). Whitehead took the Sophist to be primarily about ouvo.~t~ ('power') and found (...) in it many of the central ideas of process theology.2 Heidegger thought it articulated the 'average concept of being in general'.3 In Cornford's view the Sophist is mainly about truth and falsehood. Ackrill, Frede and most analytic philosophers think it is about predication.4 Stanley Rosen treats it as a metaphysico-aesthetic dialogue: in his view it is about the relation of images to originals.5 As far as the title of the dialogue goes, however, opinion is almost universal. Do not be misled: 'the definition of the sophist' observed Archer-Hind 'is simply a piece of pungent satire'6 and he added that 'we may be sure that (Plato] cared little about defining the sophist, but very much about the metaphysical questions to which the process of definition was to give rise'.7 The most spectacular case of agreement with this judgment can be found in Cornford, who omits to translate the sections on the definition of the sophist because, as he says 'the modern reader ... might be wearied'.8. (shrink)

We explore the finite model theory of the characterisation theorems for modal and guarded fragments of first-order logic over transition systems and relational structures of width two. A new construction of locally acyclic bisimilar covers provides a useful analogue of the well known tree-like unravellings that can be used for the purposes of finite model theory. Together with various other finitary bisimulation respecting model transformations, and Ehrenfeucht–Fraïssé game arguments, these covers allow us to upgrade finite approximations for full bisimulation (...) equivalence towards approximations for elementary equivalence. These techniques are used to prove several ramifications of the van Benthem–Rosen characterisation theorem of basic modal logic for refinements of ordinary bisimulation equivalence, both in the sense of classical and of finite model theory. (shrink)

Qualitative coalitional games (QCGs) were introduced as abstract formal models of goal-oriented cooperative systems. A QCG is a game in which each agent is assumed to have some goal to achieve, and in which agents must typically cooperate with others in order to satisfy their goals. In this paper, we show how it is possible to reason about QCGs using Coalition Logic (CL), a formalism intended to facilitate reasoning about coalitional powers in game-like multiagent systems. We introduce a correspondence relation (...) between QCGs and interpretations for CL, which defines the circumstances under which a CL interpretation correctly characterises a QCG. The complexity of deciding correspondence between QCGs and interpretations for CL is shown to vary from being tractable up to Πp 2-complete, depending on the representation chosen for the QCG and interpretation. We then show how various properties and solution concepts of QCGs can be characterised as CL formula schemes. The ideas are illustrated via a detailed worked example, in which we demonstrate how a model checker can be deployed to investigate whether a particular system has the properties in question. (shrink)

Irrespective of the short academic history of Christian spirituality, a vast number of academic and popular publications ensued and is still dynamically growing. Many definitions have been proposed to define (Christian) spirituality. Spirituality is also no longer connected only to religion, although in this research the focus will fall on Christian spirituality. This research intends to partake in the continuing academic dialogue to define Christian spirituality. Christian spirituality is interpreted from the perspective of the divine-human conversation. This research consists of (...) three sections. In the first section, a working definition of Christian spirituality is formulated. In the second section, various aspects that constitute spiritualities are distinguished and discussed. In the last section, the constituents of Christian spirituality are pointed out and are reviewed from a conversational perspective. The focus will be on ‘the experience of the divine’ when living a life that resonates with the Christian life. (shrink)

A small large cardinal upper bound in $V$ for proving when certain subsets of $\omega_1$ are precisely those constructible from a real is given. In the core model we find an exact equivalence in terms of the length of the mouse order; we show that $\forall B \subseteq \omega_1 \lbrack B$ is universally Baire $\Leftrightarrow B \in L\lbrack r \rbrack$ for some real $r\rbrack$ is preserved under set-sized forcing extensions if and only if there are arbitrarily large "admissibly measurable" cardinals.

The relation between near continuity and sequential continuity for mappings between metric spaces is explored constructively. It is also shown that the classical implications “near continuity implies sequential continuity” and “near continuity implies apart continuity” are essentially nonconstructive.

It is a great pleasure to have the opportunity to contribute to this volume dedicated to the critical celebration of Stephen Schiffer’s very considerable philosophical achievements. My focus will be on his recent work on vagueness.1 The broad direction of Schiffer’s researches in this area has been to give priority to what we may call the characterisation problem: the problem of saying what the vagueness of expressions of natural language consists in or, more specifically – since Schiffer takes it (...) as a given that the vagueness he is targeting consist in a propensity of vague expressions to give rise to borderline cases —the problem of saying what being a borderline case of the concept expressed by a vague expression consists in. This has not been a main preoccupation of most of the work in the field since the vagueness “boom” started in the mid 1970s. There has been a tendency to jump straight into devising semantic theories for vague languages, usually aimed at twin desiderata of saving classical logic and dissolving the various paradoxes of vagueness, with a principal focus on the standard sorites, and occasional glances at the Forced March, and others.2 Of course, such work has inevitably implicated commitment to broad conceptions of vagueness, and of borderline cases, of various kinds. The classical epistemicist approach, for example, conceives of borderline cases as instances whose correct classification in terms of the relevant concept is, for reasons it attempts to explain, unknowable. Semantic indeterminist approaches, by contrast, tend (often implicitly) to conceive of borderline cases as items to which the concept in question neither applies nor fails to apply and as coming about because our practice with the concept leaves it, in effect, merely partially defined and so ‘gappy’. A variation on this, still semantic indeterminist, regards vagueness as consisting in a phenomenon akin to divided reference, whereby a predicate, for example, may be associated with a range of extensionally distinct best candidates to be the property it refers to; borderline cases are then items which exemplify some but not all of these properties.. (shrink)

We seek means of distinguishing logical knowledge from other kinds of knowledge, especially mathematics. The attempt is restricted to classical two-valued logic and assumes that the basic notion in logic is the proposition. First, we explain the distinction between the parts and the moments of a whole, and theories of ?sortal terms?, two theories that will feature prominently. Second, we propose that logic comprises four ?momental sectors?: the propositional and the functional calculi, the calculus of asserted propositions, and rules for (...) (in)valid deduction, inference or substitution. Third, we elaborate on two neglected features of logic: the various modes of negating some part(s) of a proposition R, not only its ?external? negation not-R; and the assertion of R in the pair of propositions ?it is (un)true that R? belonging to the neglected logic of asserted propositions, which is usually left unstated. We also address the overlooked task of testing the asserted truth-value of R. Fourth, we locate logic among other foundational studies: set theory and other theories of collections, metamathematics, axiomatisation, definitions, model theory, and abstract and operator algebras. Fifth, we test this characterisation in two important contexts: the formulation of some logical paradoxes, especially the propositional ones; and indirect proof-methods, especially that by contradiction. The outcomes differ for asserted propositions from those for unasserted ones. Finally, we reflect upon self-referring self-reference, and on the relationships between logical and mathematical knowledge. A subject index is appended. (shrink)

We generalise the concept of clique width to structures of arbitrary signature and cardinality. We present characterisations of clique width in terms of decompositions of a structure and via interpretations in trees. Several model-theoretic properties of clique width are investigated including VC-dimension and preservation of finite clique width under elementary extensions and compactness.

Regarding the dichotomy between applied science and pure science, there are two apparently paradoxical facts. First, they are distinguishable. Second, the outcomes of pure sciences (e.g. scientific theories and models) are applicable to producing the outcomes of applied sciences (e.g. technological artefacts) and vice versa. Addressing the functional roles of applied and pure science, i.e. to produce design representation and science representation, respectively, I propose a new characterisation of the dichotomy that explains these two facts.

A small large cardinal upper bound in V for proving when certain subsets of ω 1 (including the universally Baire subsets) are precisely those constructible from a real is given. In the core model we find an exact equivalence in terms of the length of the mouse order; we show that $\forall B \subseteq \omega_1 \lbrack B$ is universally Baire $\Leftrightarrow B \in L\lbrack r \rbrack$ for some real r] is preserved under set-sized forcing extensions if and only if there (...) are arbitrarily large "admissibly measurable" cardinals. (shrink)