28,751 research outputs found
Consensus theories: an oriented survey
This article surveys seven directions of consensus theories: Arrowian results, federation consensus rules, metric consensus rules, tournament solutions, restricted domains, abstract consensus theories, algorithmic and complexity issues. This survey is oriented in the sense that it is mainly – but not exclusively – concentrated on the most significant results obtained, sometimes with other searchers, by a team of French searchers who are or were full or associate members of the Centre d'Analyse et de Mathématique Sociale (CAMS).Consensus theories ; Arrowian results ; aggregation rules ; metric consensus rules ; median ; tournament solutions ; restricted domains ; lower valuations ; median semilattice ; complexity
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
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
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
Group deliberation and the transformation ofjudgments: an impossibility result
While a large social-choice-theoretic literature discusses the aggregation ofindividual judgments into collective ones, there is relatively little formalwork on the transformation of individual judgments in group deliberation. Idevelop a model of judgment transformation and prove a baselineimpossibility result: Any judgment transformation function satisfying someinitially plausible condition is the identity function, under which no opinionchange occurs. I identify escape routes from this impossibility result andargue that successful group deliberation must be 'holistic': individualscannot generally revise their judgments on a proposition based on judgmentson that proposition alone but must take other propositions into account too. Idiscuss the significance of these findings for democratic theory.group deliberation, judgment aggregation, judgmenttransformation, belief revision
Approval-Based Shortlisting
Shortlisting is the task of reducing a long list of alternatives to a
(smaller) set of best or most suitable alternatives from which a final winner
will be chosen. Shortlisting is often used in the nomination process of awards
or in recommender systems to display featured objects. In this paper, we
analyze shortlisting methods that are based on approval data, a common type of
preferences. Furthermore, we assume that the size of the shortlist, i.e., the
number of best or most suitable alternatives, is not fixed but determined by
the shortlisting method. We axiomatically analyze established and new
shortlisting methods and complement this analysis with an experimental
evaluation based on biased voters and noisy quality estimates. Our results lead
to recommendations which shortlisting methods to use, depending on the desired
properties
Aggregating Dependency Graphs into Voting Agendas in Multi-Issue Elections
Many collective decision making problems have a
combinatorial structure: the agents involved must
decide on multiple issues and their preferences over
one issue may depend on the choices adopted for
some of the others. Voting is an attractive method
for making collective decisions, but conducting a
multi-issue election is challenging. On the one hand,
requiring agents to vote by expressing their preferences
over all combinations of issues is computationally
infeasible; on the other, decomposing the
problem into several elections on smaller sets of
issues can lead to paradoxical outcomes. Any pragmatic
method for running a multi-issue election will
have to balance these two concerns. We identify
and analyse the problem of generating an agenda
for a given election, specifying which issues to vote
on together in local elections and in which order to
schedule those local elections
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