125 research outputs found
Modelling Multilateral Negotiation in Linear Logic
We show how to embed a framework for multilateral negotiation,
in which a group of agents implement a sequence of deals
concerning the exchange of a number of resources, into linear logic.
In this model, multisets of goods, allocations of resources, preferences
of agents, and deals are all modelled as formulas of linear logic.
Whether or not a proposed deal is rational, given the preferences of
the agents concerned, reduces to a question of provability, as does
the question of whether there exists a sequence of deals leading to an
allocation with certain desirable properties, such as maximising social
welfare. Thus, linear logic provides a formal basis for modelling
convergence properties in distributed resource allocation
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
Modelling Combinatorial Auctions in Linear Logic
We show that linear logic can serve as an expressive framework
in which to model a rich variety of combinatorial auction
mechanisms. Due to its resource-sensitive nature, linear
logic can easily represent bids in combinatorial auctions in
which goods may be sold in multiple units, and we show
how it naturally generalises several bidding languages familiar
from the literature. Moreover, the winner determination
problem, i.e., the problem of computing an allocation of
goods to bidders producing a certain amount of revenue for
the auctioneer, can be modelled as the problem of finding a
proof for a particular linear logic sequent
Epistemic Selection of Costly Alternatives: The Case of Participatory Budgeting
We initiate the study of voting rules for participatory budgeting using the
so-called epistemic approach, where one interprets votes as noisy reflections
of some ground truth regarding the objectively best set of projects to fund.
Using this approach, we first show that both the most studied rules in the
literature and the most widely used rule in practice cannot be justified on
epistemic grounds: they cannot be interpreted as maximum likelihood estimators,
whatever assumptions we make about the accuracy of voters. Focusing then on
welfare-maximising rules, we obtain both positive and negative results
regarding epistemic guarantees
07431 Executive Summary -- Computational Issues in Social Choice
Computational social choice is an interdisciplinary field of study at the interface
of social choice theory and computer science, with knowledge flowing in either direction.
On the one hand, computational social choice is concerned with importing concepts and procedures from
social choice theory for solving questions that arise in computer science and AI application domains.
This is typically the case for managing societies of autonomous agents, which calls for negotiation
and voting procedures. On the other hand, computational social choice is concerned with importing
notions and methods from computer science for solving questions originally stemming from social choice,
for instance by providing new perspectives on the problem of manipulation and control in elections.
This Dagstuhl Seminar has been devoted to the presentation of recent results and an exchange
of ideas in this growing research field
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
Fair division under ordinal preferences: Computing envy-free allocations of indivisible goods
Abstract We study the problem of fairly dividing a set of goods amongst a group of agents, when those agents have preferences that are ordinal relations over alternative bundles of goods (rather than utility functions) and when our knowledge of those preferences is incomplete. The incompleteness of the preferences stems from the fact that each agent reports their preferences by means of an expression of bounded size in a compact preference representation language. Specifically, we assume that each agent only provides a ranking of individual goods (rather than of bundles). In this context, we consider the algorithmic problem of deciding whether there exists an allocation that is possibly (or necessarily) envy-free, given the incomplete preference information available, if in addition some mild economic efficiency criteria need to be satisfied. We provide simple characterisations, giving rise to simple algorithms, for some instances of the problem, and computational complexity results, establishing the intractability of the problem, for others
Expressive Power of Weighted Propositional Formulas for Cardinal Preference Modelling
As proposed in various places, a set of propositional formulas, each associated with a numerical weight, can be used to model the preferences of an agent in combinatorial domains. If the range of possible choices can be represented by the set of possible assignments of propositional symbols to truth values, then the utility of an assignment is given by the sum of the weights of the formulas it satisfies. Our aim in this paper is twofold: (1) to establish correspondences between certain types of weighted formulas and well-known classes of utility functions (such as monotonic, concave or k-additive functions); and (2) to obtain results on the comparative succinctness of different types of weighted formulas for representing the same class of utility functions
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