30 research outputs found
Complexity of Judgment Aggregation
We analyse the computational complexity of three problems in judgment aggregation:
(1) computing a collective judgment from a profile of individual judgments (the winner
determination problem); (2) deciding whether a given agent can influence the outcome
of a judgment aggregation procedure in her favour by reporting insincere judgments (the
strategic manipulation problem); and (3) deciding whether a given judgment aggregation
scenario is guaranteed to result in a logically consistent outcome, independently from what
the judgments supplied by the individuals are (the problem of the safety of the agenda).
We provide results both for specific aggregation procedures (the quota rules, the premisebased
procedure, and a distance-based procedure) and for classes of aggregation procedures
characterised in terms of fundamental axioms
A Logic for Reasoning about Group Norms
We present a number of modal logics to reason about group norms. As a preliminary
step, we discuss the ontological status of the group to which the norms are
applied, by adapting the classification made by Christian List of collective attitudes
into aggregated, common, and corporate attitudes. Accordingly, we shall introduce
modality to capture aggregated, common, and corporate group norms. We investigate
then the principles for reasoning about those types of modalities. Finally, we discuss
the relationship between group norms and types of collective responsibility
The Ontology of Group Agency
We present an ontological analysis of the notion of group agency developed
by Christian List and Philip Pettit. We focus on this notion as it allows us to
neatly distinguish groups, organizations, corporations – to which we may ascribe
agency – from mere aggregates of individuals. We develop a module for group
agency within a foundational ontology and we apply it to organizations
Preservation of Semantic Properties during the Aggregation of Abstract Argumentation Frameworks
An abstract argumentation framework can be used to model the argumentative
stance of an agent at a high level of abstraction, by indicating for every pair
of arguments that is being considered in a debate whether the first attacks the
second. When modelling a group of agents engaged in a debate, we may wish to
aggregate their individual argumentation frameworks to obtain a single such
framework that reflects the consensus of the group. Even when agents disagree
on many details, there may well be high-level agreement on important semantic
properties, such as the acceptability of a given argument. Using techniques
from social choice theory, we analyse under what circumstances such semantic
properties agreed upon by the individual agents can be preserved under
aggregation.Comment: In Proceedings TARK 2017, arXiv:1707.0825
Ontology Merging as Social Choice
The problem of merging several ontologies has important applications in the Semantic Web, medical ontology engineering
and other domains where information from several distinct sources needs to be integrated in a coherent manner.We propose
to view ontology merging as a problem of social choice, i.e. as a problem of aggregating the input of a set of individuals
into an adequate collective decision. That is, we propose to view ontology merging as ontology aggregation. As a first step in
this direction, we formulate several desirable properties for ontology aggregators, we identify the incompatibility of some of
these properties, and we define and analyse several simple aggregation procedures. Our approach is closely related to work
in judgment aggregation, but with the crucial difference that we adopt an open world assumption, by distinguishing between
facts not included in an agent’s ontology and facts explicitly negated in an agent’s ontology
A partial taxonomy of judgment aggregation rules, and their properties
The literature on judgment aggregation is moving from studying impossibility
results regarding aggregation rules towards studying specific judgment
aggregation rules. Here we give a structured list of most rules that have been
proposed and studied recently in the literature, together with various
properties of such rules. We first focus on the majority-preservation property,
which generalizes Condorcet-consistency, and identify which of the rules
satisfy it. We study the inclusion relationships that hold between the rules.
Finally, we consider two forms of unanimity, monotonicity, homogeneity, and
reinforcement, and we identify which of the rules satisfy these properties
Logics for modelling collective attitudes
We introduce a number of logics to reason about collective propositional
attitudes that are defined by means of the majority rule. It is well known that majoritarian
aggregation is subject to irrationality, as the results in social choice theory and judgment
aggregation show. The proposed logics for modelling collective attitudes are based on
a substructural propositional logic that allows for circumventing inconsistent outcomes.
Individual and collective propositional attitudes, such as beliefs, desires, obligations, are
then modelled by means of minimal modalities to ensure a number of basic principles. In
this way, a viable consistent modelling of collective attitudes is obtained