eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
25
10.4230/DagSemProc.07271.1
article
07271 Abstracts Collection – Computational Social Systems and the Internet
Cramton, Peter
Müller, Rudolf
Tardos, Eva
Tennenholtz, Moshe
From 01.07. to 06.07.2007, the Dagstuhl Seminar 07271 ``Computational Social Systems and the Internet'' was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.1/DagSemProc.07271.1.pdf
Mechanism Design
Combinatorial Auctions
Social Choice Theory
Behavioral Economics
Computational Game Theory
Social Networks
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
0
10.4230/DagSemProc.07271.2
article
07271 Summary – Computational Social Systems and the Internet
Cramton, Peter
Müller, Rudolf
Tardos, Eva
Tennenholtz, Moshe
The seminar "Computational Social Systems and the Internet" facilitated a very fruitful interaction between economists and computer scientists, which
intensified the understanding of the other disciplines' tool sets.
The seminar helped to pave the way to a unified theory of social systems on the Internet that takes into account both the economic and the computational
issues---and their deep interaction.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.2/DagSemProc.07271.2.pdf
Mechanism Design
Combinatorial Auctions
Social Choice Theory
Behavioral Economics
Computational Game Theory
Social Networks
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
25
10.4230/DagSemProc.07271.3
article
An Axiomatic Approach to Personalized Ranking Systems
Altman, Alon
Tennenholtz, Moshe
Personalized ranking systems and trust systems are an
essential tool for collaboration in a multi-agent
environment. In these systems, trust relations between
many agents are aggregated to produce a personalized
trust rating of the agents. In this paper we introduce
the first extensive axiomatic study of this setting,
and explore a wide array of well-known and new
personalized ranking systems. We adapt several axioms
(basic criteria) from the literature on global ranking
systems to the context of personalized ranking systems,
and fully classify the set of systems that satisfy all
of these axioms. We further show that all these axioms
are necessary for this result.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.3/DagSemProc.07271.3.pdf
Ranking systems
trust
axiomatization
incentives
mechanism design
game theory
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
15
10.4230/DagSemProc.07271.4
article
Anonymity-Proof Voting Rules
Conitzer, Vincent
A (randomized, anonymous) voting rule maps any multiset of total orders of
(aka. votes over) a fixed set of alternatives to a probability distribution over these alternatives. A voting rule f is neutral if it treats all alternatives symmetrically. It satisfies participation if no voter ever benefits from not casting her vote. It is falsename-proof if no voter ever benefits from casting additional (potentially different)
votes. It is anonymity-proof if it satisfies participation and it is false-name-proof. We
show that the class of anonymity-proof neutral voting rules consists exactly of the
rules of the following form. With some probability kf in [0, 1], the rule chooses an
alternative at random. With probability 1-kf , the rule first draws a pair of alternatives
at random. If every vote prefers the same alternative between the two (and there
is at least one vote), then the rule chooses that alternative. Otherwise, the rule flips a
fair coin to decide between the two alternatives.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.4/DagSemProc.07271.4.pdf
Mechanism design
social choice
false-name-proofness
verifying identities
combinatorial auctions
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
0
10.4230/DagSemProc.07271.5
article
Auction Design with Avoidable Fixed Costs: An Experimental Approach
Elmaghraby, Wedad
Larson, Nathan
Advances in information technology and computational power have
opened the doors for auctioneers to explore a range of auction
formats by considering varying degrees of bid expressivity and
different payment rule, e.g., single price vs. discriminatory prices.
While it is clear that one can design more complicated auctions,
it is still not clear if should do so and which auction parameters
have the greatest impact on the performance on cost and efficiency.
The purpose of this paper is to gain some insight into this question, via analytical and experimental methods.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.5/DagSemProc.07271.5.pdf
Auctions
Experimental
Procurement
Synergies
Asymmetric Bidders
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
0
10.4230/DagSemProc.07271.6
article
Incentive Compatible Regression Learning
Dekel, Ofer
Fischer, Felix
Procaccia, Ariel D.
We initiate the study of incentives in a general machine learning framework. We focus on a game theoretic regression learning setting where private information is elicited from multiple agents, which are interested in different distributions over the sample space. This conflict potentially gives rise to untruthfulness on the part of the agents. In the restricted but important case when distributions are degenerate, and under mild assumptions, we show that agents are motivated to tell the truth. In a more general setting, we study the power and limitations of mechanisms without payments. We finally establish that, in the general setting, the VCG mechanism goes a long way in guaranteeing truthfulness and efficiency.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.6/DagSemProc.07271.6.pdf
Machine learning
regression
mechanism design
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
9
10.4230/DagSemProc.07271.7
article
Inefficiency of equilibria in query auctions with continuous valuations
Grigorieva, Elena
Herings, P. Jean-Jacques
Müller, Rudolf
Vermeulen, Dries
We show that, when bidders have continuous valuations, any ex post
equilibrium in an ex post individually rational query auction can only be
ex post efficient when the running time of the auction is infinite for almost
all realizations of valuations of the bidders. In contrast we show that,
when we allow for inefficient allocations with arbitrarily small probability,
there is a query auction (to be more specific, a bisection auction) that attains this level of approximate efficiency in equilibrium, while additionally the
running time of the auction in equilibrium is finite for all realizations of
valuations.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.7/DagSemProc.07271.7.pdf
Query auctions
ex post equilibrium
efficiency
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
2
10.4230/DagSemProc.07271.8
article
Item Pricing for Revenue Maximization in Combinatorial Auctions
Balcan, Maria-Florina
Consider the problem of a retailer with various goods for sale, attempting to set prices to maximize revenue. If customers have separate valuations over the different goods, and these are known to the retailer, then the goods can be priced separately and the problem is not so difficult. However, when customers have valuations over sets of items, this becomes a combinatorial auction problem, and the problem becomes computationally hard even when valuations are fully known in advance. In this talk we present some simple randomized algorithms and mechanisms for a number of interesting cases of this problem, both in the limited and unlimited supply setting.
This talk is based on joint work with Avrim Blum and Yishay Mansour.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.8/DagSemProc.07271.8.pdf
Item Pricing
Revenue Maximizing
Combinatorial Auctions
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
0
10.4230/DagSemProc.07271.9
article
License Auctions with Royalty Contracts for (Winners and) Losers
Wolfstetter, Elmar
Giebe, Thomas
This paper revisits the licensing of a non--drastic process innovation by an outside innovator to a Cournot oligopoly. We propose a new mechanism that combines a restrictive license auction with royalty licensing. This mechanism is more profitable than standard license auctions, auctioning royalty contracts, fixed--fee licensing, pure royalty licensing, and two-part tariffs. The key features are that royalty contracts are auctioned and that losers of the auction are granted the option to sign a royalty contract. Remarkably, combining royalties for winners and losers makes the
integer constraint concerning the number of licenses irrelevant.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.9/DagSemProc.07271.9.pdf
Auctions
Patents
Licensing
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
10
10.4230/DagSemProc.07271.10
article
Limited Verification of Identities to Induce False-Name-Proofness
Conitzer, Vincent
In open, anonymous environments such as the
Internet, mechanism design is complicated by
the fact that a single agent can participate in
the mechanism under multiple identifiers. One
way to address this is to design false-name-proof
mechanisms, which choose the outcome in such
a way that agents have no incentive to use more
than one identifier. Unfortunately, there are inherent
limitations on what can be achieved with
false-name-proof mechanisms, and at least in
some cases, these limitations are crippling. An
alternative approach is to verify the identities of
all agents. This imposes significant overhead and
removes any benefits from anonymity.
In this paper, we propose a middle ground. Based
on the reported preferences, we check, for various
subsets of the reports, whether the reports in
the subset were all submitted by different agents.
If they were not, then we discard some of them.
We characterize when such a limited verification
protocol induces false-name-proofness for a
mechanism, that is, when the combination of the
mechanism and the verification protocol gives
the agents no incentive to use multiple identi-
fiers. This characterization leads to various optimization
problems for minimizing verification
effort. We study how to solve these problems.
Throughout, we use combinatorial auctions (using
the Clarke mechanism) and majority voting
as examples.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.10/DagSemProc.07271.10.pdf
Mechanism design
social choice
false-name-proofness
verifying identities
combinatorial auctions
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
4
10.4230/DagSemProc.07271.11
article
On Revenue Equivalence in Truthful Mechanisms
Heydenreich, Birgit
Müller, Rudolf
Uetz, Marc
Vohra, Rakesh
The property of an allocation rule to be implementable in dominant strategies
by a unique payment scheme is called revenue equivalence. In this paper we give a
characterization of revenue equivalence based on a graph theoretic interpretation of
the incentive compatibility constraints. The characterization holds for any (possibly
infinite) outcome space and many of the known results about revenue equivalence
are immediate consequences.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.11/DagSemProc.07271.11.pdf
Mechanism Design
Revenue Equivalence
Graph Theory
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
7
10.4230/DagSemProc.07271.12
article
Reducing Costly Information Acquisition in Auctions
Larson, Kate
Most auction research assumes that potential bidders have private information about their willingness to pay for an item. In reality, bidders often have to go through a costly information-gathering process in order to learn their valuations. Recent attempts at modelling this phenomena has brought to light complex strategic behavior arising from information-gathering, and has shown that traditional approaches to auction and mechanism design are not able to overcome it.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.12/DagSemProc.07271.12.pdf
Auctions
Information Gathering
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
12
10.4230/DagSemProc.07271.13
article
Signalling Preferences in Interviewing Markets
Lee, Robin S.
Schwarz, Michael A.
The process of match formation in matching markets can be divided into three parts: information sharing, investments in information acquisition, and the formation of matches based on available information. The last stage where agents are assumed to know their preferences has been studied in seminal work of Gale and Shapley (1962), and a model of second stage costly information acquisition is introduced and studied in Lee and Schwarz (2007). This paper focuses on the first stage – information sharing – and examines mechanisms which allow workers to signal their preferences over matching partners prior to the assignment of interviews. The incentives of firms and workers vis-a-vis information revelation are partially aligned – all other things being equal, a worker prefers to have an interview with a firm that is high in his preference ranking and a firm prefers to invest in interviewing a worker who ranks a firm highly because such worker is more likely to accept a job if
offered. However, the incentives are far from being perfectly aligned. For instance, if firms pay the full cost of interviewing, each worker would prefer to have as many interviews as possible, and in a world with bilateral communication no information is revealed as each workers would want to tell each firm that it is his first choice. But if communication is moderated through an intermediary or there is a restriction on the number of messages a worker can send, then cheap talk becomes informative. Currently existing market institutions that facilitate information exchange prior to interviewing are discussed.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.13/DagSemProc.07271.13.pdf
Cheap talk
job search
labor market
matching,
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
7
10.4230/DagSemProc.07271.14
article
Social Comparisons and Contributions to Online Communities: A Field Experiment on MovieLens
Chen, Yan
Harper, Maxwell
Konstan, Joseph
Li, Sherry
We explore the use of social comparison theory as a natural
mechanism to increase contributions to an online movie
recommendation community by investigating the effects of social
information on user behavior in an online field experiment. We
find that, after receiving behavioral information about
the median user's total number of movie ratings, users below the
median demonstrate a 530% increase in the number of monthly movie
ratings, while those above the median decrease their monthly
ratings by 62%. Movements from both ends converge towards the
median, indicating conformity towards a newly-established social
norm in a community where such a norm had been absent.
Furthermore, the social information has a more dramatic effect on
those below the median, suggesting an interaction between
conformity and competitive preferences. When given
outcome information about the average user's net benefit
score from the system, consistent with social preference theory,
users with net benefit scores above average contribute 94% of the
new updates in the database. In both treatments, we find a highly
significant Red Queen Effect.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.14/DagSemProc.07271.14.pdf
Social comparison
conformity
public goods
embedded online field experiment
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
1
10.4230/DagSemProc.07271.15
article
Strategic Behavior in Multi-unit Assignment Problems: Theory and Evidence from Course Allocations
Budish, Eric
Cantillon, Estelle
This paper analyses the assignment problem when agents have multi-unit demand. Applications include task assignment in a team, course allocation, sport drafts and any other allocation problem where money does not play a role in balancing supply and demand. There is no known allocation mechanism that is ex-post efficient, strategyproof and minimally fair, and practical solutions must therefore trade off these different aspects. We study such a specific mechanism used at Harvard Business School to allocate courses to students. We argue that students in the HBS mechanism have an incentive to overreport their preferences for popular courses, that this incentive does not vanish with the size of the market and that it results in increased congestion. We confirm these predictions with detailed data on reported preferences and behavior in the HBS mechanism. We show that strategic behavior hurts students but that it might still be preferable to random serial dictatorship over course bundles, a strategyproof alternative.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.15/DagSemProc.07271.15.pdf
Course allocation
market design
assignment
multi-unit demand
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2007-10-02
7271
1
12
10.4230/DagSemProc.07271.16
article
Strategy-proof assignment with a vanishing budget surplus
Moulin, Hervé
A VCG mechanism to assign p identical objects is feasible is cash transfers yield no deficit. The efficiency loss of such a mechanism is the worst ratio of budget surplus to efficient surplus. We compute the optimal efficiency loss for all n and p, when we also require Voluntary Participation as well as when we do not. Without the VP requirement, the optimal efficiency loss converges to zero uniformly in p, and exponentially fast if p is fixed. With the VP requirement asymptotic budget balance is only true is p is not larger than n/2.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol07271/DagSemProc.07271.16/DagSemProc.07271.16.pdf
VCG mechanisms
assignment
asymptotic budget balance
worst case analysis