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.

Recently Shakurov pioneered the study of subalgebras of diagonalizable algebras of theories of arithmetic. We show that his results extend to weaker theories.

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 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 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.

This paper discusses the merits and faults of a Note by Vittorino Grossi, published in this journal , concerning a new Italian translation of Augustine’s bestseller, City of God, with an introduction by Domenico Marafioti . The Author discusses the divergence of interpretations of Augustine’s works.

Mc Taggart's celebrated proof of the unreality of time is a chain of implications whose final step asserts that the A-series (i.e. the classification of events as past, present or future) is intrinsically contradictory. This is widely believed to be the heart of the argument, and it is where most attempted refutations have been addressed; yet, it is also the only part of the proof which may be generalised to other contexts, since none of the notions involved in it is (...) specifically temporal. In fact, as I show in the first part of the paper, McTaggart's refutation of the A-series can be easily interpreted in mathematical terms; subsequently, in order to strengthen my claim, I apply the same framework by analogy to the cases of space, modality, and personal identity. Therefore, either McTaggart's proof as a whole may be extended to each of these notions, or it must embed some distinctly temporal element in one of the steps leading up to the contradiction of the A-series. I conclude by suggesting where this element might lay, and by hinting at what I believe to be the true logical fallacy of the proof. (shrink)

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)

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)

This chapter introduces readers to the empirical questions at issue in debates over gendered pronouns and assesses the plausibility of various possible answers to these questions. It has two parts. The first is a general introduction to the linguistics and psychology of grammatical gender. The second focuses on the meanings of gendered pronouns in English. It begins with a discussion of some methodological limitations of empirical approaches to the topic and the normative implications of those limitations. It then argues against (...) three simple theories of the semantics of gendered pronouns in English and proposes an alternative that fares better: the Gender-First View. Finally, it discusses the singular use of 'they' and its connection to nonbinary gender identities. (shrink)

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 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)

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.

The contribution examines the notion of occasionalismo sensista, or also known by the expression of formalismo sensista, that the Italian philosopher Adelchi Baratono was proposing in the ’30s and ’40s of the twentieth century. Best known for his dense volume, Il mondo sensibile. Introduzione all’estetica, Baratono is among the first thinkers of his time in Italy to start a confrontation with Kantian criticism in aesthetic context, looking groundwork for an alternative route to the one proposed by the Italian Neo-idealism. In (...) fact, against the absolutization of the subject, which Baratono ascribes, in particular, to the thought of Giovanni Gentile, he affirms the profound otherness of subject and object in front of which philosophy is bound to be wrecked. In this perspective, the “sensible world” for Baratono is in itself, regardless of the knowing subject, because everything is resolved in the “world within and around us”. In this perspective, Baratono affirms that the feeling is all this, that is something without which are neither perception nor the concept and even the idea. The feeling, therefore, far from being considered the first stage of knowledge, is the real existence. (shrink)

The present essay seeks to analyze the reflections on cinematographic art proposed by Jean-Luc Nancy, referring in particular to his L’Évidence du film. Abbas Kiarostami (2001) as well as to other studies where the author reconsiders the concepts of image and gaze. The specifity of films lies in “evidence”, which is a way to affirm the finite character of existence-presence. Cinema addresses the world without any form of realism. It is reality itself to open out to the image. What results (...) is a possible gaze which is no longer on representation and nor can it be a representative gaze. This gaze does not look at any object; the very act of seeing can be seen through it. (shrink)

In December 1924 Wolfgang Pauli proposed the idea of an inner degree of freedom of the electron, which he insisted should be thought of as genuinely quantum mechanical in nature. Shortly thereafter Ralph Kronig and, independently, Samuel Goudsmit and George Uhlenbeck took up a less radical stance by suggesting that this degree of freedom somehow corresponded to an inner rotational motion, though it was unclear from the very beginning how literal one was actually supposed to take this picture, since it (...) was immediately recognised that it would very likely lead to serious problems with Special Relativity if the model were to reproduce the electron's values for mass, charge, angular momentum, and magnetic moment. However, probably due to the then overwhelming impression that classical concepts were generally insufficient for the proper description of microscopic phenomena, a more detailed reasoning was never given. In this contribution I shall investigate in some detail what the restrictions on the physical quantities just mentioned are, if they are to be reproduced by rather simple classical models of the electron within the framework of Special Relativity. It turns out that surface stresses play a decisive role and that the question of whether a classical model for the electron does indeed contradict Special Relativity can only be answered on the basis of an exact solution, which has hitherto not been given. (shrink)

O objetivo deste artigo é refletir sobre o mecanismo da negação como uma estratégia psicopolítica que articula o movimento bolsonarista. Como método de trabalho, realizamos uma discussão teórica sobre alguns aspectos do movimento bolsonarista que são estruturados pelo negacionismo. Empregamos os conceitos da psicologia política, da esquizoanálise e da psicanálise de grupo para analisar este fenômeno. Para discutir os mecanismos de negação, constatamos quatro características principais: (i) a negação como estratégia discursiva, (ii) a lógica cognitiva da negatividade, (iii) a produção (...) do antagonismo coletivo e (iv) a micropolítica do ódio, que é anterior à necessidade de um líder. PALAVRAS-CHAVE: Psicologia Política. Extremismo político. Esquizoanálise. Grupo. (shrink)