1,720,998 research outputs found
Verità e Giustificazione degli Asserti Temporali
Full text linkL'articolo si occupa delle principali teorie semantiche basate su una nozione temporale di verità
Modal logics with propositional constants
No full textQuesta dissertazione cerca di fornire un trattamento unificato delle costanti proposizionali in logica modale. I linguaggi arricchiti con costanti vengono usati almeno a partire dalla metà del secolo scorso, ma ancora non è stato fatto uno studio sistematico. Il principale contributo del mio lavoro consiste nello sviluppo di un approccio semantico basato su strutture con insiemi di interpretazioni possibili per le costanti proposizionali, chiamati restrizioni specifiche; tali strutture sono confrontate con quelle in cui ogni costante ha una interpretazione fissa, solitamente utilizzate nella letteratura. Viene mostrato che la presenza di restrizioni specifiche permette di definire la nozione di strict range di una formula (traducibile come "varietà stretta di modelli"), che risulta essere importante per questioni di teoria dei modelli. Inoltre, l'approccio semantico qui introdotto viene usato per formulare sistemi di logica del tempo il cui linguaggio include operatori primitivi di contingenza; per tali sistemi si dimostrano risultati di caratterizzazione in riferimento a diverse classi di strutture temporali. Infine, la tesi propone una generalizzazione dello studio dei linguaggi modali arricchiti passando da linguaggi con costanti proposizionali a linguaggi con quantificatori proposizionali e di questi ultimi viene studiata la teoria della dimostrazione con sistemi di deduzione naturale etichettata.This dissertation aims at providing a unified treatment of propositional constants in modal logic. Languages enriched with constants have been used at least from the Fifties, but a systematic study of them is still not available.The main contribution consists in the development of a semantic approach based on structures with sets of possible interpretations for propositional constants, called specific restrictions; such structures are compared with those in which every constant has a fixed interpretation, usually adopted in the literature. We show that the presence of specific restrictions allows one to define the notion of strict range of a formula, that turns out to be important for model-theoretic purposes. Furthermore, we use the semantic approach here introduced to develop systems of temporal logic whose language includes primitive operators of contingency, showing that propositional constants are useful to obtain characterization results with reference to different classes of temporal frames. Finally, we move from languages with propositional constants to languages with propositional quantifiers (the latter being intended as a generalization of the former) and analyse their proof theory in natural deduction calculi
Two Temporal Logics of Contingency
No full textThis work concerns the use of operators for past and future contingency in Priorean temporal logic. We will develop a system named C_t, whose language includes a propositional constant and prove that (i) C_t is complete with respect to a certain class of general frames and (ii) the usual operators for past and future necessity are definable in such system. Furthermore, we will introduce the extension C_t(lin) that can be interpreted on linear and transitive general frames. The theoretical result of the current work is that contingency can be treated as a primitive notion in reasoning about temporal modalities
A Unified Semantics for a Family of Modal Logics with Propositional Constants
No full textThis article concerns the metatheory of a class of modal logics whose language includes propositional constants of various kinds. The main novelties are the use of general frames with specific restrictions and the definition of the strict range of a formula. Many examples from the literature are treated within the framework provided and some traditional model-theoretic issues such as preservation results concerning the validity of formulas and definability results concerning frame properties are addressed
Influence of World Knowledge and Context on the Comprehension of Natural Language Translation of Logical Formulas
No full textIn this paper we present an approach to conditional reasoning tasks based on two main ideas. The first idea is
that, in
contrast with
what is usually assumed, an
‘
if... then...
’
sentence is not an adequate translation in natural
language of a logical formula containing a material implication as
its
principal operator. The second idea is that
when subjects are required to check the validity
of a sentence in a task, their inferences are not driven uniquely
by the content of the sentence, but also by other information embedded in the task scenario and, eventually, by
their knowledge about the topic (i.e. information stored in memory)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The Good, the Bad and the Right: Formal Reductions among Deontic Concepts
Full text linkThe present article provides a taxonomic analysis of bimodal logics of normative ideality and normative awfulness, two notions whose meaning is here explained in terms of the moral values pursued by a given community. Furthermore, the article addresses the traditional problem of a reduction among deontic concepts: we explore the possibility of defining other relevant normative notions, such as obligation, explicit permission and Hohfeldian relations, in terms of ideality and awfulness. Some proposals in this respect, which have been formulated in the literature over the years, are here improved and discussed with reference to the various logics that we will introduce
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