We study the theory of K-vector spaces with a predicate for the union X of an infinite family of independent subspaces. We show that if K is infinite then the theory is complete and admits quantifier elimination in the language of K-vector spaces with predicates for the n-fold sums of X with itself. If K is finite this is no longer true, but we still have that a natural completion is near-model-complete.

By recent work on some conjectures of Pillay, each definably compact group G in a saturated o-minimal expansion of an ordered field has a normal "infinitesimal subgroup" G00 such that the quotient G/G00, equipped with the "logic topology", is a compact (real) Lie group. Our first result is that the functor G → G/G00 sends exact sequences of definably compact groups into exact sequences of Lie groups. We then study the connections between the Lie group G/G00 and the o-minimal spectrum (...) G̃ of G. We prove that G/G00 is a topological quotient of G̃. We thus obtain a natural homomorphism ψ* from the cohomology of G/G00 to the (Čech-)cohomology of G̃. We show that if G00 satisfies a suitable contractibility conjecture then $\widetilde{G^{00}}$ is acyclic in Čech cohomology and ψ* is an isomorphism. Finally we prove the conjecture in some special cases. (shrink)

The topology of definable sets in an o-minimal expansion of a group is not fully understood due to the lack of a triangulation theorem. Despite the general validity of the cell decomposition theorem, we do not know whether any definably compact set is a definable CW-complex. Moreover the closure of an o-minimal cell can have arbitrarily high Betti numbers. Nevertheless we prove that the cohomology groups of a definably compact set over an o-minimal expansion of a group are finitely generated (...) and invariant under elementary extensions and expansions of the language. (shrink)

PA is Peano arithmetic. The formula $\operatorname{Interp}_\mathrm{PA}(\alpha, \beta)$ is a formalization of the assertion that the theory PA + α interprets the theory PA + β (the variables α and β are intended to range over codes of sentences of PA). We extend Solovay's modal analysis of the formalized provability predicate of PA, Pr PA (x), to the case of the formalized interpretability relation $\operatorname{Interp}_\mathrm{PA}(x, y)$ . The relevant modal logic, in addition to the usual provability operator `□', has a (...) binary operator ` $\triangleright$ ' to be interpreted as the formalized interpretability relation. We give an axiomatization and a decision procedure for the class of those modal formulas that express valid interpretability principles (for every assignment of the atomic modal formulas to sentences of PA). Our results continue to hold if we replace the base theory PA with Zermelo-Fraenkel set theory, but not with Gödel-Bernays set theory. This sensitivity to the base theory shows that the language is quite expressive. Our proof uses in an essential way earlier work done by A. Visser, D. de Jongh, and F. Veltman on this problem. (shrink)

Skolem studied the germs at infinity of the smallest class of real valued functions on the positive real line containing the constant $1$, the identity function ${\mathbf {x}}$, and such that whenever f and g are in the set, $f+g,fg$ and $f^g$ are in the set. This set of germs is well ordered and Skolem conjectured that its order type is epsilon-zero. Van den Dries and Levitz computed the order type of the fragment below $2^{2^{\mathbf {x}}}$. Here we prove that (...) the set of asymptotic classes within any Archimedean class of Skolem functions has order type $\omega $. As a consequence we obtain, for each positive integer n, an upper bound for the fragment below $2^{n^{\mathbf {x}}}$. We deduce an epsilon-zero upper bound for the fragment below $2^{{\mathbf {x}}^{\mathbf {x}}}$, improving the previous epsilon-omega bound by Levitz. A novel feature of our approach is the use of Conway’s surreal number for asymptotic calculations. (shrink)

Skolem studied the germs at infinity of the smallest class of real valued functions on the positive real line containing the constant $1$, the identity function ${\mathbf {x}}$, and such that whenever f and g are in the set, $f+g,fg$ and $f^g$ are in the set. This set of germs is well ordered and Skolem conjectured that its order type is epsilon-zero. Van den Dries and Levitz computed the order type of the fragment below $2^{2^{\mathbf {x}}}$. Here we prove that (...) the set of asymptotic classes within any Archimedean class of Skolem functions has order type $\omega $. As a consequence we obtain, for each positive integer n, an upper bound for the fragment below $2^{n^{\mathbf {x}}}$. We deduce an epsilon-zero upper bound for the fragment below $2^{{\mathbf {x}}^{\mathbf {x}}}$, improving the previous epsilon-omega bound by Levitz. A novel feature of our approach is the use of Conway’s surreal number for asymptotic calculations. (shrink)

We prove that the theory IΔ0, extended by a weak version of the Δ0-Pigeonhole Principle, proves that every integer is the sum of four squares (Lagrange's theorem). Since the required weak version is derivable from the theory IΔ0 + ∀x (xlog(x) exists), our results give a positive answer to a question of Macintyre (1986). In the rest of the paper we consider the number-theoretical consequences of a new combinatorial principle, the ‘Δ0-Equipartition Principle’ (Δ0EQ). In particular we give a new proof, (...) which can be formalized in IΔ0 + Δ0EQ, of the fact that every prime of the form 4n + 1 is the sum of two squares. (shrink)

We prove that if G is a group definable in a saturated o-minimal structure, then G has no infinite descending chain of type-definable subgroups of bounded index. Equivalently, G has a smallest type-definable subgroup G00 of bounded index and G/G00 equipped with the “logic topology” is a compact Lie group. These results give partial answers to some conjectures of the fourth author.

We develop an intersection theory for definable Cp-manifolds in an o-minimal expansion of a real closed field and we prove the invariance of the intersection numbers under definable Cp-homotopies . In particular we define the intersection number of two definable submanifolds of complementary dimensions, the Brouwer degree and the winding numbers. We illustrate the theory by deriving in the o-minimal context the Brouwer fixed point theorem, the Jordan-Brouwer separation theorem and the invariance of the Lefschetz numbers under definable Cp-homotopies. A. (...) Pillay has shown that any definable group admits an abstract manifold structure. We apply the intersection theory to definable groups after proving an embedding theorem for abstract definably compact Cp-manifolds. In particular using the Lefschetz fixed point theorem we show that the Lefschetz number of the identity map on a definably compact group, which in the classical case coincides with the Euler characteristic, is zero. (shrink)

Models of normal open induction are those normal discretely ordered rings whose nonnegative part satisfy Peano's axioms for open formulas in the language of ordered semirings. (Where normal means integrally closed in its fraction field.) In 1964 Shepherdson gave a recursive nonstandard model of open induction. His model is not normal and does not have any infinite prime elements. In this paper we present a recursive nonstandard model of normal open induction with an unbounded set of infinite prime elements.

Let M be an o-minimal expansion of an ordered field. Let φ be a formula in the language of ordered domains. In this note we establish some topological properties which are transferred from $\varphi^M$ to $\varphi^R$ and vice versa. Then, we apply these transfer results to give a new proof of a result of M. Edmundo-based on the work of A. Strzebonski-showing the existence of torsion points in any definably compact group defined in an o-minimal expansion of an ordered field.

Let PLω be the provability logic of IΔ0 + ω1. We prove some containments of the form L ⊆ PLω < Th(C) where L is the provability logic of PA and Th(C) is a suitable class of Kripke frames.

Orthogonality in model theory captures the idea of absence of non-trivial interactions between definable sets. We introduce a somewhat opposite notion of cohesiveness, capturing the idea of interaction among all parts of a given definable set. A cohesive set is indecomposable, in the sense that if it is internal to the product of two orthogonal sets, then it is internal to one of the two. We prove that a definable group in an o-minimal structure is a product of cohesive orthogonal (...) subsets. If the group has dimension one, or it is definably simple, then it is itself cohesive. As an application, we show that an abelian group definable in the disjoint union of finitely many o-minimal structures is a quotient, by a discrete normal subgroup, of a direct product of locally definable groups in the single structures. (shrink)

Wilkie 5 397) proved a “theorem of the complement” which implies that in order to establish the o-minimality of an expansion of with C∞ functions it suffices to obtain uniform bounds on the number of connected components of quantifier free definable sets. He deduced that any expansion of with a family of Pfaffian functions is o-minimal. We prove an effective version of Wilkie's theorem of the complement, so in particular given an expansion of the ordered field with finitely many C∞ (...) functions, if there are uniform and computable upper bounds on the number of connected components of quantifier free definable sets, then there are uniform and computable bounds for all definable sets. In such a case the theory of the structure is effectively o-minimal: there is a recursively axiomatized subtheory such that each of its models is o-minimal. This implies the effective o-minimality of any expansion of with Pfaffian functions. We apply our results to the open problem of the decidability of the theory of the real field with the exponential function. We show that the decidability is implied by a positive answer to the following problem ): given a language L expanding the language of ordered rings, if an L-sentence is true in every L-structure expanding the ordered field of real numbers, then it is true in every o-minimal L-structure expanding any real closed field. (shrink)

We prove that if G is a Δ 0 -definable function on the natural numbers and F = Π i = 0 n G , then F is also Δ 0 -definable. Moreover, the inductive properties of F can be proved inside the theory IΔ 0.

By recent work on some conjectures of Pillay, each definably compact group in a saturated o-minimal structure is an extension of a compact Lie group by a torsion free normal divisible subgroup, called its infinitesimal subgroup. We show that the infinitesimal subgroup is cohomologically acyclic. This implies that the functorial correspondence between definably compact groups and Lie groups preserves the cohomology.

Some computational phenomena rely essentially on pragmatic considerations, and seem to undermine the independence of the specification from the implementation. These include software development, deviant uses, esoteric languages and recent data-driven applications. To account for them, the interaction between pragmatics, epistemology and ontology in computational artefacts seems essential, indicating the need to recover the role of the language metaphor. We propose a User Levels (ULs) structure as a pragmatic complement to the Levels of Abstraction (LoAs)-based structure defining the ontology and (...) epistemology of computational artefacts. ULs identify a flexible hierarchy in which users bear their own semantic and normative requirements, possibly competing with the logical specification. We formulate a notion of computational act intended in its pragmatic sense, alongside pragmatic versions of implementation and correctness. (shrink)

The Wealth of Ideas, first published in 2005, traces the history of economic thought, from its prehistory to the present day. In this eloquently written, scientifically rigorous and well documented book, chapters on William Petty, Adam Smith, David Ricardo, Karl Marx, William Stanley Jevons, Carl Menger, Léon Walras, Alfred Marshall, John Maynard Keynes, Joseph Schumpeter and Piero Sraffa alternate with chapters on other important figures and on debates of the period. Economic thought is seen as developing between two opposite poles: (...) a subjective one, based on the ideas of scarcity and utility, and an objective one based on the notions of physical costs and surplus. Professor Roncaglia focuses on the different views of the economy and society and on their evolution over time and critically evaluates the foundations of the scarcity-utility approach in comparison with the Classical/Keynesian approach. (shrink)

Philosophers distinguish between having a property essentially and having it accidentally. The way the distinction has been drawn suggests that it is modal in character, and so that it can be captured in terms of necessity, or cognate notions. The present chapter takes the suggestion at face value by considering a number of modal characterizations of the essential/accidental distinction that have been articulated and discussed since the early 20th century, as well as some of the challenges that they face.

How and to what extent do people take into account the intentions of others? Alessandro Duranti sets out to answer this question, showing that the role of intentions in human interaction is variable across cultures and contexts. Through careful analysis of data collected over three decades in US and Pacific societies, Duranti demonstrates that, in some communities, social actors avoid intentional discourse, focusing on the consequences of actions rather than on their alleged original goals. In other cases, he argues, (...) people do speculate about their own intentions or guess the intentions of others, including in some societies where it was previously assumed they avoid doing so. To account for such variation, Duranti proposes an 'intentional continuum', a concept that draws from phenomenology and the detailed analysis of face-to-face interaction. A combination of new essays and classic re-evaluations, the book draws together findings from anthropology, linguistics and philosophy to offer a penetrating account of the role of intentions in defining human action. (shrink)

Wittgenstein has written a great number of remarks relevant to aesthetical issues: he has questioned the relation between aesthetics and psychology as well as the status of our norms of judgment; he has drawn philosophers attention to such topics as aspect-seeing and aspect-dawning, and has brought insights into the nature of our aesthetic reactions. The examination of this wide range of topics is far from being completed, and the purpose of this book is to contribute to such completion. It gathers (...) both papers discussing some of Wittgenstein s most provocative and intriguing statements on aesthetics, and papers bringing out their implications for art critic and art history, as well as their significance to epistemology and to the study of human mind.". (shrink)

The aim of this paper is to present a system of modal connexive logic based on a situation semantics. In general, modal connexive logics are extensions of standard modal logics that incorporate Aristotle’s and Boethius’ theses, that is the thesis that a sentence cannot imply its negation and the thesis that a sentence cannot imply a pair of contradictory sentences. A key problem in devising a connexive logic is to come up with a system that is both sufficiently strong to (...) fulfill some specific connexive theses and sufficiently well-motivated from a semantical point of view. The approach proposed here tries to address this problem by defining an appropriate connexive relation in terms of more basic notions. The result is a well-motivated system of modal connexive logic that nicely fits in both with the traditional ideas concerning the connexive conditional and with the current developments in connexive logic. (shrink)

L’ambientazione dell’itinerario che qui si propone rinvia ad un’ermeneutica del diritto che concentra l’attenzione non su un settore – costituito da metodologie e principi ai quali attingere per la soluzione di conflitti nella prassi –, ma su una riflessione rigorosa. Tale ordine di pensiero muove dalla filosofia aristotelica del De Interpretatione, sino ai problemi della globalizzazione, trattati interrogandosi se l’ermeneutica occupi o meno un posto prioritario nel complesso universum giuridico. Si prende atto che l’arte dell’interpretazione appare sostituibile con un insieme (...) di teorie argomentative che, con il loro management, rischiano di banalizzare i concetti della responsabilità personale nella vita quotidiana dell’amministrazione della giustizia. (shrink)

This book contains essential contributions to enrich and broaden the application field of pragmatics. It provides an example of how the fruitful reflections and refined conceptual distinctions born in the philosophical field can find a practical application in addressing social, cognitive, clinical, and psychological problems. Its chapters address, from different points of view, the relationship between pragmatic linguistics and philosophy, and outline the possible application of pragmatic theories to different domains. Developed during the third Pragmasophia international conference, whose name is (...) derived from the Greek terms πρᾶγμα (action, fact) and σοφία (knowledge, science), the book aligns itself with its aim to study human actions and activities and how they take shape through language. But ‘Pragma’ and ‘Sophia’ also signal another purpose: highlighting the importance of creating links between empirical investigations on language use, and more traditional philosophical approaches. In this reading, ‘Pragma’ represents the experimental goal devoted to analysing and interpreting language facts. In contrast, the term ‘Sophia’ recalls the original vocation of past philosophers to pursue an ideal of ‘pure knowledge’, disconnected from any practical-economic interest. While maintaining the conference's original purpose of encouraging productive comparisons between different approaches, the book consists of two sections: first, on philosophical approaches, recalls more theoretical aspects (closer to the term ‘Sophia’); the second, ‘Inferential and Cognitive Pragmatics,’ addresses more practical issues affecting domains such as Greek literature, pragmatic disorders, dictionary entries, and speech analysis. The reader, whether in linguists, philosophy or psychology, obtains a complete overview of the most advanced current research lines, both theoretical and empirical, and thus contributes to broadening the scope of pragmatics. (shrink)

Ted Sider has famously argued that existence, in the unrestricted sense of ontology, cannot be vague, as long as vagueness is modeled by means of precisifications. The first section of Chapter 9 exposes some controversial assumptions underlying Sider’s alleged reductio of vague existence. The upshot of the discussion is that, although existence cannot be vague, it can be super-vague, i.e. higher-order vague, for all orders. The second section develops and defends a novel framework, dubbed negative supervaluationary semantics, which makes room (...) for the possibility of super-vague existence. (shrink)

Keenan (1987) observed that trivial determiners built from basic existential determiners (e.g.,either zero or else more than zero) are allowed inthere-insertion contexts, and that trivial determiners built from basic non-existential determiners (e.g.,either all or else not all) are not. This result is unexpected under the analyses ofthere-sentences proposed in Barwise and Cooper (1981), Higginbotham (1987), and Keenan (1987). I argue that the class of NPs barred from the postverbal position ofthere-sentences (strong NPs) is correctly characterized in presuppositional terms, as suggested (...) in de Jong and Verkuyl (1985) and Lumsden (1988). According to this characterization, strong NPs share one of the defining components of definiteness proposed in Heim (1982), namely the Descriptive Content Condition (DCC). How to derive the prohibition against strong NPs inthere-insertion contexts (definiteness effect) from the fact that strong NPs meet the DCC is not obvious, however. I argue that accounting for this prohibition involves regarding the XP-coda in [there be NP XP] as providing the contextual domain for the interpretation of the postverbal NP. (shrink)

Philosophers have rightly condemned lookism—that is, discrimination in favor of attractive people or against unattractive people—in education, the justice system, the workplace and elsewhere. Surprisingly, however, the almost universal preference for attractive romantic and sexual partners has rarely received serious ethical scrutiny. On its face, it’s unclear whether this is a form of discrimination we should reject or tolerate. I consider arguments for both views. On the one hand, a strong case can be made that preferring attractive partners is bad. (...) The idea is that choosing partners based on looks seems essentially similar to other objectionable forms of discrimination. (In particular, the preference for attractive partners is arguably both unfair and harmful to a significant degree.) One can try to resist this conclusion in several ways. I consider three possible replies. The first has to do with the possibility of controlling our partner preferences. The second pertains to attractiveness and “good genes”. The last attempts to link certain aspects of attractiveness to a prospective partner’s personality and values. I argue that the first two replies fail conclusively, while the third only amounts to a limited defense of a particular kind of attractiveness preference. So the idea that we should often avoid preferring attractive partners is compelling. (shrink)

A number of companies allocate ownership rights to stakeholders different from shareholders, despite the fact that the law attributes these rights to the equity holders. This article contributes to an understanding of this evidence by developing a contingency model for the allocation of ownership rights. The model sheds light on why companies, despite pressures from the law, vary in their allocation of ownership rights. The model is based on the assumption that corporations increase their chance to survive and prosper if (...) the stakeholders supplying “critical contributions” receive the ownership rights. According to the model, “critical” contributions involve (1) contractual problems due to specific investments, long-term relationships, and low measurability; (2) the assumption of the uncertainty resting on the company; and (3) the supply of scarce and valuable resources. The model is dynamic because it also provides a basis for understanding why the allocation of ownership rights changes with time. Finally, the article presents the strategies companies can use to realize an efficient distribution of ownership rights among their stakeholders. (shrink)