The tree-based data structure of △-tree for propositional formulas is introduced in an improved and optimised form. The △-trees allow a compact representation for negation normal forms as well as for a number of reduction strategies in order to consider only those occurrences of literals which are relevant for the satisfiability of the input formula. These reduction strategies are divided into two subsets (meaning- and satisfiability-preserving transformations) and can be used to decrease the size of a negation normal form A (...) at (at most) quadratic cost. The reduction strategies are aimed at decreasing the number of required branchings and, therefore, these strategies allow to limit the size of the search space for the SAT problem. (shrink)

The tree-based data structure of -tree for propositional formulas is introduced in an improved and optimised form. The -trees allow a compact representation for negation normal forms as well as for a number of reduction strategies in order to consider only those occurrences of literals which are relevant for the satisfiability of the input formula. These reduction strategies are divided into two subsets (meaning- and satisfiability-preserving transformations) and can be used to decrease the size of a negation normal form A (...) at (at most) quadratic cost. The reduction strategies are aimed at decreasing the number of required branchings and, therefore, these strategies allow to limit the size of the search space for the SAT problem. (shrink)

In previous works, we presented a modification of the usual possible world semantics by introducing an independent temporal structure in each world and using accessibility functions to represent the relation among them. Different properties ofthe accessibility functions have been considered and axiomatic systems which define these properties have been given. Only a few ofthese systems have been proved tobe complete. The aim ofthis paper is to make a progress in the study ofcompleteness for functional systems. For this end, we use (...) indexes as names for temporal flows and give new proofs of completeness. Specifically, we focus our attention on the system which defines injectivity, because the system which defines this property without using indexes was proved to be incomplete in previous works. The only system considered which remains incomplete is the one which defines surjectivity, even ifwe consider a sequence ofnatural extensions ofthe previous one. (shrink)

ABSTRACT In this paper we present a new semantic approach for propositional linear temporal logic with discrete time, strongly based in the well-order of IN (the set of natural numbers). We consider temporal connectives which express precedence, posteriority and simultaneity, and they provide a family of expressively complete temporal logics. The selection of the new semantics and connectives used in this work was principally to obtain a suitable executable temporal logic, which can be used for the specification and control of (...) process behaviour in discrete time in a similar way to thai presented by D. Gabbay in [GAB 89], Our new approach has two advantages: firstly, the connectives are defined intuitively so that they have interpretations which relate to properties of interest in real systems; secondly, it provides a new semantics that facilitates simpler proofs of many valid formulas and metatheorems. To confirm this second advantage, we use our semantics to give a formal proof of the Separation Theorem for one of these logics (specifically LN3). The great interest of this Separation Theorem for the executable temporal logic is emphasised by D. Gabbay in [GAB 89], [GAB 88]. (shrink)

ABSTRACT Most theorem provers for Classical Logic transform the input formula into a particular normal form. This tranformation is done before the execution of the algorithm or it is integrated into the deductive algorithm. This situation is no different for Non-Classical Logics and, particularly, for Temporal Logics. However, unlike classical logic, temporal logic does not provide an extension of the notion of non negative normal form. In this work, we define a temporal negative normal form for the future fragment of (...) the linear time propositional temporal logic, named FNext. The definition saves as much information as possible about implicants and implicates of the input formula and its subformulas. This property is the novelty of this normal form; for example, in [Fis97] the normal form is guided by the separation property and in [Ven86] the normal form provided prepares the input formula to be treated by a resolution method. Moreover, we also introduce an algorithm having linear cost, which transforms the input formula into a temporal negative normal form. Furthermore, in this work we present a new structure and a set of operators over it that allows us to efficiently manage the information about unitary implicants and implicates contained in the subformulae. (shrink)

This book constitutes the refereed proceedings of the European Workshop on Logics in Artificial Intelligence, JELIA 2000, held in Malaga, Spain in September/October 2000. The 24 revised full papers presented together with three invited papers were carefully reviewed and selected out of 60 submissions. The papers are organized in topical sections on knowledge representation, reasoning about actions, belief revision, theorem proving, argumentation, agents, decidability and complexity, updates, and preferences.

El propósito de esta conferencia es el examen crítico de aspectos fundamentalesdel análisis filosófico, en las representativas vertientes de la prácticaanalítica del segundo Wittgenstein y la de dos de los más conspicuos analistas oxonienses: Ryle y Austin. Por razones de espacio, se centrará la discusión casi enteramente en el modelo wittgensteiniano, en la esperanza de que los resultados de aquélla sean claramente extensibles al otro modelo en todo lopertinente.Las principales metas perseguidas serán las de mostrar que el análisis filosófico no (...) puede (en absoluto, en algunas de las formas contempladas; sin restricciones, en otras) atribuirse, según los casos, las cualidades derivables de los desiderata de hacer a la filosofía i) puramente descriptiva; ii) esencial y efectivamente terapéutica; iii) no promotora de tesis filosóficas; y iv) dependiente,en sus raíces, de una exclusiva fuente de sapiencia lingüísticamenteinfusa, que es el lenguaje como depositario de lo que Moore (1972, p. 70)llamó "visión del mundo del sentido común"; una fuente a la que hay quedefender y usar sólo para rechazar las ilusiones de la filosofía, o para extraer elementos que contribuyan al desarrollo de doctrinas.Un recurso de los que se emplearán en esta breve exploración será un recordatorio, no precisamente entendido en sentido wittgensteiniano, del papelde la argumentación en el quehacer filosófico y de las modalidades que ellaadopta para contraponer la argumentación con los tipos de análisis mencionados,con miras a poner al descubierto las peculiaridades que interesa contemplar en esta oportunidad. (shrink)

A cross-cultural survey experiment revealed a dominant tendency to rely on a rule’s letter over its spirit when deciding which behaviors violate the rule. This tendency varied markedly across (k = 15) countries, owing to variation in the impact of moral appraisals on judgments of rule violation. Compared with laypeople, legal experts were more inclined to disregard their moral evaluations of the acts altogether and consequently exhibited stronger textualist tendencies. Finally, we evaluated a plausible mechanism for the emergence of textualism: (...) in a two-player coordination game, incentives to coordinate in the absence of communication reinforced participants’ adherence to rules’ literal meaning. Together, these studies (total n = 5,794) help clarify the origins and allure of textualism, especially in the law. Within heterogeneous communities in which members diverge in their moral appraisals involving a rule’s purpose, the rule’s literal meaning provides a clear focal point—an identifiable point of agreement enabling coordinated interpretation among citizens, lawmakers, and judges. (shrink)

The extent to which people anticipate and are influenced by the potential future consequences of their current behavior is called Consideration of Future Consequences. A well-established tool to measure this construct is the 14-item Consideration of Future Consequences Scale. The CFC-14 has shown appropriate psychometric properties in several languages. This scale comprises two factors: the CFC-Immediate and the CFC-Future. The main goal of this study was to assess the psychometric properties and internal consistency of the CFC-14 Scale in Spanish, using (...) an Argentine sample. A secondary goal was to determine its convergent validity with impulsivity, and determine differences across gender and age groups. Using a web-based survey, we collected data from 512 participants aged 13-74 years. Confirmatory Factor Analysis showed a 2-factor model as the best solution for 13-items version. Standardized regression weights ranged from.50 to.66 for CFC-F and between.43 and.83 for CFC-I. Composite reliability was also adequate: CFC-F achieve? =.80 and CFC-I? =.82. There were no differences across gender and age. The CFC-F subscale and UPPS-P subscales correlations, were negative and significant, highlighting the negative and moderate correlation between CFC-F and the lack of premeditation, a dimension strictly related to intertemporal decisions making. Thus, CFC-14 has adequate psychometric properties in an Argentinian population, although more studies are necessary to determine the robustness of these findings. (shrink)

In this paper we show that the class of fork squares has a complete orthodox axiomatization in fork arrow logic (FAL). This result may be seen as an orthodox counterpart of Venema's non-orthodox axiomatization for the class of squares in arrow logic. FAL is the modal logic of fork algebras (FAs) just as arrow logic is the modal logic of relation algebras (RAs). FAs extend RAs by a binary fork operator and are axiomatized by adding three equations to RAs equational (...) axiomatization. A proper FA is an algebra of relations where the fork is induced by an injective operation coding pair formation. In contrast to RAs, FAs are representable by proper ones and their equational theory has the expressive power of full first-order logic. A square semantics (the set of arrows is ᵎ x ᵎ for some set ᵎ) for arrow logic was defined by Y. Venema. Due to the negative results about the finite axiomatizability of representable RAs, Venema provided a non-orthodox finite axiomatization for arrow logic by adding a new rule governing the applications of a difference operator. We address here the question of extending the type of relational structures to define orthodox axiomatizations for the class of squares. Given the connections between this problem and the finitization problem addressed by I. Németi, we suspect that this cannot be done by using only logical operations. The modal version of the FA equations provides an orthodox axiomatization for FAL which is complete in view of the representability of FAs. Here we review this result and carry it further to prove that this orthodox axiomatization for FAL also axiomatizes the class of fork squares. (shrink)

The majority of Dutch physicians feel pressure when dealing with a request for euthanasia or physician-assisted suicide. This study aimed to explore the content of this pressure as experienced by general practitioners. We conducted semistructured in-depth interviews with 15 Dutch GPs, focusing on actual cases. The interviews were transcribed and analysed with use of the framework method. Six categories of pressure GPs experienced in dealing with EAS requests were revealed: emotional blackmail, control and direction by others, doubts about fulfilling the (...) criteria, counterpressure by patient’s relatives, time pressure around referred patients and organisational pressure. We conclude that the pressure can be attributable to the patient–physician relationship and/or the relationship between the physician and the patient’s relative, the inherent complexity of the decision itself and the circumstances under which the decision has to be made. To prevent physicians to cross their personal boundaries in dealing with EAS request all these different sources of pressure will have to be taken into account. (shrink)