We characterize the collapse of Buss' bounded arithmetic in terms of the provable collapse of the polynomial time hierarchy. We include also some general model-theoretical investigations on fragments of bounded arithmetic.

We show that every model of IΔ0 has an end extension to a model of a theory where log-space computable function are formalizable. We also show the existence of an isomorphism between models of IΔ0 and models of linear arithmetic LA.

Let be a saturated model of inaccessible cardinality, and let be arbitrary. Let denote the expansion of with a new predicate for. Write for the collection of subsets such that ≡. We prove that if the VC-dimension of is finite then is externally definable.

We present a simple and completely model-theoretical proof of a strengthening of a theorem of Ajtai: The independence of the pigeonhole principle from IΔ0. With regard to strength, the theorem proved here corresponds to the complexity/proof-theoretical results of [10] and [14], but a different combinatorics is used. Techniques inspired by Razborov [11] replace those derived from Håstad [8]. This leads to a much shorter and very direct construction.

We construct two recursive models of fragments of set theory. We also show that the fragments of Kripke-Platek set theory that prove -induction for -formulas have no recursive models but the standard model of the hereditarily finite sets.

We prove that there are uncountably many sets that are low for the class of Schnorr random reals. We give a purely recursion theoretic characterization of these sets and show that they all have Turing degree incomparable to 0'. This contrasts with a result of Kučera and Terwijn [5] on sets that are low for the class of Martin-Löf random reals.

We present some algebraic tools useful to the study of the expressive power of bounded formulas in second-order arithmetic (alternatively, second-order formulas in finite models). The techniques presented here come from Boolean circuit complexity and are adapted to the context of arithmetic. The purpose of this article is to expose them to a public with interests ranging from arithmetic to finite model theory. Our exposition is self-contained.

We study a real valued propositional logic with unbounded positive and negative truth values that we call ‐valued logic. Such a logic is semantically equivalent to continuous propositional logic, with a different choice of connectives. After presenting the deduction machinery and the semantics of ‐valued logic, we prove a completeness theorem for finite theories. Then we define unital and Archimedean theories, in accordance with the theory of Riesz spaces. In the unital setting, we prove the equivalence of consistency and satisfiability (...) and an approximated completeness theorem similar to the one that holds for continuous propositional logic. Eventually, among unital theories, we characterize Archimedean theories as those for which strong completeness holds. We also point out that ‐valued logic provides alternative calculi for Łukasiewicz logic and for propositional continuous logic. (shrink)

We compare two different notions of generic expansions of countable saturated structures. One kind of genericity is related to existential closure, and another is defined via topological properties and Baire category theory. The second type of genericity was first formulated by Truss for automorphisms. We work with a later generalization, due to Ivanov, to finite tuples of predicates and functions. Let $N$ be a countable saturated model of some complete theory $T$ , and let $(N,\sigma)$ denote an expansion of $N$ (...) to the signature $L_{0}$ which is a model of some universal theory $T_{0}$ . We prove that when all existentially closed models of $T_{0}$ have the same existential theory, $(N,\sigma)$ is Truss generic if and only if $(N,\sigma)$ is an e-atomic model. When $T$ is $\omega$ -categorical and $T_{0}$ has a model companion $T_{\mathrm {mc}}$ , the e-atomic models are simply the atomic models of $T_{\mathrm {mc}}$. (shrink)

We use the model theoretic notion of coheir to give short proofs of old and new theorems in Ramsey Theory. As an illustration we start from Ramsey's theorem itself. Then we prove Hindman's theorem and the Hales-Jewett theorem. Finally, we prove the two Ramsey theoretic principles that have among their consequences partition theorems due to Carlson and to Gowers.

Le Traité Théologico-Politique, publié anonymement en 1670, fut sans doute le livre le plus scandaleux du XVIIe siècle, et pour cause : l'emploi d'une méthode critique radicale pour dévoiler les mystères du pouvoir théologique et politique faisait de cet ouvrage un traité aussi stimulant que polémique. Après trois cent cinquante ans, le Traité demeure un modèle de réflexion sur la politique, la philologie, la métaphysique et la religion. Dans ce volume, le lecteur trouvera un commentaire suivi de l'ouvrage. Grâce au (...) travail collectif des vingt-huit contributeurs, il pourra comprendre le détail du discours de Spinoza ainsi que saisir la trame de fond de la pensée spinoziste. L'ouvrage se compose de deux parties : le commentaire proprement dit et une section consacrée aux principaux problèmes qui animent le débat contemporain sur Spinoza. (shrink)

Multiple authorship is so common and pervasive in our world that it is tempting to take it for granted. Prior to the twentieth century, however, multiple authorship was exceedingly rare.

In this paper we argue that data science is a coherent and novel approach to empirical problems that, in its most general form, does not build understanding about phenomena. Within the new type of mathematization at work in data science, mathematical methods are not selected because of any relevance for a problem at hand; mathematical methods are applied to a specific problem only by `forcing’, i.e. on the basis of their ability to reorganize the data for further analysis and the (...) intrinsic richness of their mathematical structure. In particular, we argue that deep learning neural networks are best understood within the context of forcing optimization methods. We finally explore the broader question of the appropriateness of data science methods in solving problems. We argue that this question should not be interpreted as a search for a correspondence between phenomena and specific solutions found by data science methods; rather, it is the internal structure of data science methods that is open to precise forms of understanding. (shrink)

Réunit des textes d'auteurs français des XVIIe et XVIIIe s. évoquant Saint-Augustin.

Perhaps no philosopher is more of a conundrum than Nietzsche, the solitary rebel, poet, wayfarer, anti-revolutionary Aufklärer and theorist of aristocratic radicalism. His accusers identify in his 'superman' the origins of Nazism, and thus issue an irrevocable condemnation; his defenders pursue a hermeneutics of innocence founded ultimately in allegory. In a work that constitutes the most important contribution to Nietzschean studies in recent decades, Domenico Losurdo instead pursues a less reductive strategy. Taking literally the ruthless implications of Nietzsche's anti-democratic (...) thinking - his celebration of slavery, of war and colonial expansion, and eugenics - he nevertheless refuses to treat these from the perspective of the mid-twentieth century. In doing so, he restores Nietzsche's works to their complex nineteenth-century context, and presents a more compelling account of the importance of Nietzsche as philosopher than can be expected from his many contemporary apologists. (shrink)

This article delves into Blaise Pascal’s religious philosophy, focusing on his use of the phrase “Scio cui credidi” (I know whom I have believed) to explore his understanding of faith. It analyzes Pascal’s “Memorial” and the “Summary of the Life of Jesus Christ”, highlighting how Christ is central to Pascal’s belief system. The discussion reveals the transformational nature of Pascal’s faith, particularly after his mystical experience on November 23, 1654. This experience is crucial in understanding his shift from a philosophical (...) to a deeply personal, Christ-centered faith. The article underscores Pascal’s journey from a scientific and philosophical perspective to an intimate, emotional resonance with Christian faith, demonstrating how his personal encounters with the divine profoundly shaped his religious perspective. (shrink)

Despite the burgeoning literature on the governance and impact of cross-sector partnerships in the past two decades, the debate on how and when these collaborative arrangements address globally relevant problems and contribute to systemic change remains open. Building upon the notion of wicked problems and the literature on governing such wicked problems, this paper defines harnessing problems in multi-stakeholder partnerships as the approach of taking into account the nature of the problem and of organizing governance processes accordingly. The paper develops (...) an innovative analytical framework that conceptualizes MSPs in terms of three governance processes harnessing three key dimensions of wicked problems. The Roundtable on Sustainable Palm Oil provides an illustrative case study on how this analytical framework describes and explains organizational change in partnerships from a problem-based perspective. The framework can be used to better understand and predict the complex relationships between MSP governance processes, systemic change and societal problems, but also as a guiding tool in organizing governance processes to continuously re-assess the problems over time and address them accordingly. (shrink)

As a reply to the commentary (Humphreys in Found Sci, 2012), we explore the methodological implications of seeing artificial neural networks as generic classification tools, we show in which sense the use of descriptions and models in data analysis is not equivalent to the original empirical use of epicycles in describing planetary motion, and we argue that agnostic science is essentially related to the type of problems we ask about a phenomenon and to the processes used to find answers.

This paper explores the relationship between business experience in cross-sector partnerships and the co-creation of what we refer to as ‘dynamic capabilities for stakeholder orientation,’ consisting of the four dimensions of sensing, interacting with, learning from and changing based on stakeholders. We argue that the co-creation of dynamic capabilities for stakeholder orientation is crucial for CSPs to create societal impact, as stakeholder-oriented organizations are more suited to deal with “wicked problems,” i.e., problems that are large, messy, and complex. By means (...) of a grounded theory approach of inductive research, we collected and interpreted data on four global agri-food companies which have heterogeneous experience in participating in CSPs. The results of this paper highlight that only companies’ capability of interacting with stakeholders continually increases, while their capabilities of sensing, learning from, and changing based on stakeholders first increase and then decrease as companies gain more experience in CSP participation. To a large extent, this can be attributed to the development of corporate strategies on sustainability after a few years of CSP participation, which entails a shift from a reactive to a proactive attitude towards sustainability issues and which may decrease the need or motivation for stakeholder orientation. These findings open up important issues for discussion and for future research on the impact of CSPs in a context of wicked problems. (shrink)

1. Itinerari cinquecenteschi -- 2. Itinerari secenteschi.