A Closeness- and Priority-Based Logical Study of Social Network Creation

This paper is part of an on-going programme on the study of the logical aspects of social network formation. It recalls the so-called social network model, discussing the properties of a notion of closeness between agents (in terms of the number of traits they have in common); then introduces an extended social network model in which different agents might assign different values to different traits, discussing the properties of the notion of weighted closeness that arises. These notions are used to define social network creation operations by means of a threshold strategy. The paper studies the properties of the social networks the updates create, providing sound and complete axiom systems for formal languages describing these updates’ effects.publishedVersio

Non-strict Interventionism: The Case Of Right-Nested Counterfactuals

The paper focuses on a recent challenge brought forward against the interventionist approach to the meaning of counterfactual conditionals. According to this objection, interventionism cannot account for the interpretation of right-nested counterfactuals, the problem being its strict interventionism. We will report on the results of an empirical study supporting the objection. Furthermore, we will extend the well-known logic of intervention with a new operator expressing an alternative notion of intervention that does away with strict interventionism (and thus can account for some critical examples). This new notion of intervention operates on the valuation of the variables in a causal model, and not on their functional dependencies.</p

A logical study of group-size based social network creation

This paper is part of an on-going research programme on the logical aspects of social network creation. In our proposed setting we make use of a notion of distance between agents, defined as the number of features distinguishing them. Following the ideas of the cognitive science literature, we build the social network by adopting a group-size approach: each agent's new social space will contain the λ agents that are closer to her. The paper studies the properties of the resulting networks, providing a sound and complete axiom system for a logical language which describes the changes that the social network creation operation brings about. This is done not only for the basic case in which the distance is relative to all basic features and the more general one in which the distance is relative to a given subset of them, but also for the more interesting scenario in which the distance is relative to a set of more complex social features

Logic of Justified Beliefs Based on Argumentation

This manuscript presents a topological argumentation framework for modelling notions of evidence-based (i.e., justified) belief. Our framework relies on so-called topological evidence models to represent the pieces of evidence that an agent has at her disposal, and it uses abstract argumentation theory to select the pieces of evidence that the agent will use to define her beliefs. The tools from abstract argumentation theory allow us to model agents who make decisions in the presence of contradictory information. Thanks to this, it is possible to define two new notions of beliefs, grounded beliefs and fully grounded beliefs. These notions are discussed in this paper, analysed and compared with the existing notion of topological justified belief. This comparison revolves around three main issues: closure under conjunction introduction, the level of consistency and their logical strength