Comparing the Reasoning Capabilities of Equilibrium Theories and Answer Set Programs

[Abstract] Answer Set Programming (ASP) is a well established logical approach in artificial intelligence that is widely used for knowledge representation and problem solving. Equilibrium logic extends answer set semantics to more general classes of programs and theories. When intertheory relations are studied in ASP, or in the more general form of equilibrium logic, they are usually understood in the form of comparisons of the answer sets or equilibrium models of theories or programs. This is the case for strong and uniform equivalence and their relativised and projective versions. However, there are many potential areas of application of ASP for which query answering is relevant and a comparison of programs in terms of what can be inferred from them may be important. We formulate and study some natural equivalence and entailment concepts for programs and theories that are couched in terms of inference and query answering. We show that, for the most part, these new intertheory relations coincide with their model-theoretic counterparts. We also extend some previous results on projective entailment for theories and for the new connective called fork.This research has received partial support from the European Cooperation in Science & Technology (COST) Action CA17124. The third author acknowledges the funding of project PID 2020-116201GB-I00 (Ministerio de Ciencia e Innovación, Spain) and also the financial support supplied by the Consellería de Educación, Universidade e Formación Profesional (accreditations GPC ED431B 2022/23 and 2019–2022 ED431G-2019/01). The last author has been supported by the Austrian Science Fund (FWF) grant Y698Xunta de Galicia; ED431B 2022/23Xunta de Galicia; ED431G-2019/0

The economics of the family: a review of the development and a bibliography of recent papers

"The paper provides an overview of the various strands of research within the Economics of the Family. Whereas traditional microeconomic analysis treats the household as a black box the New Home Economics approach by Becker/Gronau distinguishes between individuals, but family members have unitary preferences and therefore exhibit one unique, joint utility function. Within game-theoretic models of intra-family resource allocation – cooperative as non-cooperative games – the, generally different, individual preferences are determinants of all (possible) bargaining outcomes . The second part of the paper consists of a bibliography containing relevant recent papers sorted by the different approaches."[author´s abstract]"Das Papier gibt einen Überblick über die verschiedenen Forschungsströmungen der Familienökonomik. Während die traditionelle Mikroökonomie den Haushalt als ‚Black Box’ behandelt, unterscheidet der Ansatz der ‚New Home Economics’ von Becker/Gronau zwischen Individuen innerhalb eines Haushaltes, weist diesen jedoch eine gemeinsame Nutzenfunktion, demnach auch einheitliche Präferenzen, zu. Bei – kooperativen wie nicht-kooperativen – spieltheoretischen Modellen intrafamiliärer Ressourcenallokation werden die unterschiedlichen individuellen Präferenzen als bestimmende Faktoren der (möglichen) Verhandlungsergebnisse behandelt. Der zweite Teil des Papiers besteht aus einer Bibliographie, die die wichtigsten jüngeren Papiere zu den oben erwähnten Strömungen erfasst."[Autorenreferat

Explanations from contemporary quantum theories: some ontological characteristics

Početna je pozicija ovoga rada da je znanstveno znanje nepotpuno bez objašnjenja, gdje se razvojem novih teorija to znanje proširuje i produbljuje (tako što temeljne teorije objašnjavaju širi spektar pojava i postaju opdenitije primjenjive). Povijesno gledano, kvantna je teorija (početkom 20. st.), ili inicijalno 'kvantna mehanika', konačno potkopala navodni neograničeni uspjeh redukcionističke mehanistične eksplanatorne filozofije (uzevši u obzir i konceptualni dodatak koji čini Maxwellova konceptualizacija polja). Tako je ponovo otvoren put skepticizmu prema eksplanatornim ciljevima znanosti. Međutim, u posljednje vrijeme ponovo se budi i vjerovanje u temeljnu ulogu kvantne teorije, bilo kao dio fundamentalne potpune teorije ili iznova osmišljenu u okvirima ograničenja na prikupljanje informacija o osjetilno nedostupnoj ontologiji fizikalnog svijeta.The starting position of the this thesis is that scientific knowledge is incomplete without explanations, whereupon with the development of new theories our knowledge both broadens and deepens (as fundamental theories explain more and become more general). Historically, it has been quantum theory (early 20th century), or initially quantum mechanics, that finally undermined the supposed runaway success of reductionist mechanistic philosophy (modulo Maxwellian updating), re-opening the door for scepticism about the explanatory aims of science. However, recent years have seen a revival of the belief in some version of quantum theory, either as part of a fundamental complete theory or as reinvented in terms of constraints on information gathering about the underlying unobservable ontology of the physical world

Labour supply: a review of alternative approaches

This chapter surveys existing approaches to modeling labor supply and identifies important gaps in the literature that could be addressed in future research. The discussion begins with a look at recent policy reforms and labor market facts that motivate the study of labor supply. The analysis then presents a unifying framework that allows alternative empirical formulations of the labor supply model to be compared and their resulting elasticities to be interpreted. This is followed by critical reviews of alternative approaches to labor-supply modeling. The first review assesses the difference in-differences approach and its relationship to natural experiments. The second analyzes estimation with non-linear budget constraints and welfare-program participation. The third appraises developments of family labor-supply models including both the standard unitary and collective labor-supply formulations. The fourth briefly explores dynamic extensions of the labor supply model, characterizing how participation decisions, learning-by-doing, human capital accumulation and habit formation affect the analysis of the lifecycle model. At the end of each of the four broad reviews, we summarize a selection of the recent empirical findings. The concluding section asks whether the developments reviewed in this chapter place us in a better position to answer the policy-reform questions and to interpret the trends in participation and hours with which we began this review. q1999 Elsevier Science B.V. All rights reserved.

Choice logics and their computational properties

Qualitative Choice Logic (QCL) and Conjunctive Choice Logic (CCL) are formalisms for preference handling, with especially QCL being well established in the field of AI. So far, analyses of these logics need to be done on a case-by-case basis, albeit they share several common features. This calls for a more general choice logic framework, with QCL and CCL as well as some of their derivatives being particular instantiations. We provide such a framework, which allows us, on the one hand, to easily define new choice logics and, on the other hand, to examine properties of different choice logics in a uniform setting. In particular, we investigate strong equivalence, a core concept in non-classical logics for understanding formula simplification, and computational complexity. Our analysis also yields new results for QCL and CCL. For example, we show that the main reasoning task regarding preferred models is $\Theta^p_2$-complete for QCL and CCL, while being $\Delta^p_2$-complete for a newly introduced choice logic.Comment: This is an extended version of a paper of the same name to be published at IJCAI 202

Preferences, counterfactuals and maximisation: Reasoning in game theory.

This thesis explores two kinds of foundational issues in game theory. The first is concerned with the interpretation of the basic structure of a game, especially the definitions of outcomes and payoffs. This discussion leads to the second issue; namely the nature of solution concepts and their relation to both explicit and implicit assumptions in game theory concerning hypothetical reasoning. Interpreting utility functions in game theory, I argue that the notion of revealed preferences is ill-suited for counterfactual reasoning and for taking account of the implicit normativity of instrumental rationality. An alternative interpretation is outlined that treats preferences as determinants of choice. Accordingly, outcomes have to be individuated so as to capture everything that matters to an agent. I consider whether this is problematic when properties of outcomes depend on choice processes themselves. Turning to a decision theoretic problem, I question Verbeek's (2001) claim that modal outcome individuation conflicts with axioms of consequentialism. Next, I critically assess Rabin's (1993) model of fairness equilibria. Hypothesising about unilateral deviation is shown to be incompatible with belief-dependent utility definitions. Counterfactuals in games are then analysed more generally. It proves to be crucial for solution concepts whether our formal framework allows us to differentiate between indicative and subjunctive conditionals. Stalnaker's (1996) prima facie counterexample to Aumann's (1995) theorem that common knowledge of rationality implies a subgame perfect equilibrium is questioned on the grounds of a plausibility criterion. Again drawing on what has been established about the structure of a game and the meaning of its elements, Gauthier's (1986) notion of constrained maximisation, an attempt to overcome the non-cooperative equilibrium of the finitely iterated prisoner's dilemma, is shown to be incompatible with orthodox game theoretical methodology. The approach of treating the unit of agency as endogenous is addressed

Rationality and time: A multiple-self model of personal identity over time for decision and game theory.

This thesis presents extensions to formal theories of rationality in order to analyse intertemporal decisions. It offers multiple-self models of the decision-maker's personal identity over time. These models complement decision and game theory and are used to develop the new accounts of time discounting, backward induction, and preference change that are presented in this thesis. The first part of the thesis develops multiple-self models of personal identity over time. These models depict a rational decision-maker as a series of different but interconnected temporal selves. The models allow one to relax the assumption that a rational decision-maker is a diachronically stable entity. Moreover, they structurally cohere with key problems and distinctions in theories of personal identity over time. In the second part of the thesis, three problems of time in decision and game theory are analysed. Firstly, the problem of time discounting is considered. General foundations of time discounting are given in a measurement-theoretic framework. In the multiple-self interpretation of a decision-maker, the discounting factor represents the degree of connectedness between temporal selves in a person. Secondly, the reasoning method of backward induction in interactions over time is considered. Sufficient conditions for backward induction are given by formulating a belief revision policy on the basis of intrapersonal connectedness of players. Thirdly, preference change is considered. A new characterisation of diachronic inconsistency in terms of conflicts in intrapersonal connectedness is given. The multiple-self models presented here allow one to represent the internal temporal structure of decision-makers. They capture problems of the interplay between rationality, identity, and time, thereby elucidating new accounts of time discounting, backward induction, and preference change. More generally, this thesis offers a new approach to modelling the intertemporal aggregation of value, which possesses broader relevance for decision theory, the foundations of economics, social epistemology as well as environmental ethics

Lawless Universe

Can science fully comprehend the whole of the material universe? Not according to Joe Rosen.There is no question that advancements in science—especially in physics—have radically changed our concept of nature, revolutionizing our view of the universe, even of reality itself. Rosen argues, though, that the material universe in its entirety lies beyond science. Anyone who claims otherwise, who proposes a scientific Theory of Everything to explain all aspects and phenomena of nature, only misleads and misinforms. Taking science—and the scientific method—down a peg, Rosen asserts that any understanding of the whole universe, if it is to be found at all, can come only from outside science, from nonscientific modes of comprehension and insight. He believes that popularizers of science—think Stephen Hawking and Richard Dawkins—are mistaken when they declare that science is on the verge of unlocking all the secrets of the universe. Perhaps without realizing it, they have crossed into the realm of metaphysics in an attempt to explain the unexplainable. In Lawless Universe Rosen explores just how far science can go in comprehending nature. He considers the separate—but entangled—domains of science and metaphysics and examines the all-too-often ignored boundary between the objective and the subjective. Thought-provoking and controversial, Lawless Universe is a complement to, even an antidote for, books that create the misimpression that science can explain everything

L’économie comportementale et le rôle du langage dans la rationalité économique : une perspective méthodologique

In this dissertation, we propose a methodological perspective on the twofold role of language in economic rationality, economists’ uses of language to theorize it and economic agent’s uses of language to express it, can clarify three main issues (and their connections), underlying the behavioral versus standard economics debates: the issue of the theoretical unification regarding the three dimensions of economic rationality, the issue of interdisciplinarity between economics and Psychology and the positive/normative issue within models of individual behaviors. Regarding the positive/normative issue and the role of language in the behaviors of economic agents, the intention is to provide a constructive criticism of contributions from behavioral as well as standard economists. Following the entanglement thesis of philosopher Hilary Puntam and philosophers-economists Vivian Walsh and Amartya Sen, it is argued that both standard and behavioral economists propose an unsatisfying articulation between the positive and normative dimensions of models of individual behaviors; and that recognizing the entanglement of facts, values and conventions can actually be theoretically and empirically fruitful. Paying some attention to the role of language in the behaviors of economic agents may sometimes show that a seemingly irrational behavior can in fact be defended as rational; hence we argue that, and show how, the implicit axiom -- known as ‘description invariance’ -- in standard models of individual behaviors preventing the influence of language needs to be weakened (though not dropped entirely), contrary to the positions of most behavioral and standard economists.Dans cette thèse, nous proposons une perspective méthodologique sur le double rôle du langage dans la rationalité économique, les utilisations de langage par les économistes pour la théoriser et les utilisations de langage par les agents économiques pour l’exprimer, pour clarifier trois principales questions (et leurs connexions) qui sous-tendent les débats entre économie comportementale et économie standard : le problème de l’unification théorique vis-à-vis des trois dimensions de la rationalité économique, la question de l’interdisciplinarité entre économie et Psychologie, et le problème du positif/normatif dans les modèles de comportements individuels. Concernant le problème du positif/normatif et le rôle du langage dans les comportements des agents économiques, notre intention est de fournir, au-delà de la simple clarification, une critique constructive des contributions de l’économie standard comme de l’économie comportementale. Suivant la position de l’enchevêtrement du philosophe Hilary Putnam et des philosophes-économistes Vivian Walsh et Amartya Sen, il est soutenu que l’économie tant standard que comportementale propose une articulation insatisfaisante des dimensions positive et normative dans les modèles de comportements individuels; et que la reconnaissance de l’enchevêtrement de faits, de valeurs et de conventions peut être théoriquement et empiriquement fructueuse. Prêter attention au rôle du langage dans les comportements des agents économiques montre parfois qu’un comportement apparemment irrationnel peut en fait être défendu comme rationnel; c’est pourquoi nous soutenons que, et montrons comment, l'axiome implicite - connu sous le nom d’invariance à la description - dans les modèles standards de comportements individuels empêchant l’influence du langage doit être affaibli (mais pas complètement supprimé), contrairement aux positions de la plupart des économistes standards et comportementaux