TY - GEN
T1 - Sum of us
T2 - 13th Conference on Theoretical Aspects of Rationality and Knowledge, TARK 2011
AU - Alon, Noga
AU - Fischer, Felix
AU - Procaccia, Ariel
AU - Tennenholtz, Moshe
PY - 2011
Y1 - 2011
N2 - We consider the special case of approval voting when the set of agents and the set of alternatives coincide. This captures situations in which the members of an organization want to elect a president or a committee from their ranks, as well as a variety of problems in networked environments, for example in internet search, social networks like Twitter, or reputation systems like Epinions. More precisely, we look at a setting where each member of a set of n agents approves or disapproves of any other member of the set and we want to select a subset of k agents, for a given value of k, in a strategyproof and approximately efficient way. Here, strategyproofness means that no agent can improve its own chances of being selected by changing the set of other agents it approves. A mechanism is said to provide an approximation ratio of α for some α ≥ 1 if the ratio between the sum of approval scores of any set of size k and that of the set selected by the mechanism is always at most α. We show that for k ∈ {1, 2,..., n - 1}, no deterministic strategyproof mechanism can provide a finite approximation ratio. We then present a randomized strategyproof mechanism that provides an approximation ratio that is bounded from above by four for any value of k, and approaches one as k grows.
AB - We consider the special case of approval voting when the set of agents and the set of alternatives coincide. This captures situations in which the members of an organization want to elect a president or a committee from their ranks, as well as a variety of problems in networked environments, for example in internet search, social networks like Twitter, or reputation systems like Epinions. More precisely, we look at a setting where each member of a set of n agents approves or disapproves of any other member of the set and we want to select a subset of k agents, for a given value of k, in a strategyproof and approximately efficient way. Here, strategyproofness means that no agent can improve its own chances of being selected by changing the set of other agents it approves. A mechanism is said to provide an approximation ratio of α for some α ≥ 1 if the ratio between the sum of approval scores of any set of size k and that of the set selected by the mechanism is always at most α. We show that for k ∈ {1, 2,..., n - 1}, no deterministic strategyproof mechanism can provide a finite approximation ratio. We then present a randomized strategyproof mechanism that provides an approximation ratio that is bounded from above by four for any value of k, and approaches one as k grows.
KW - approval voting
KW - approximate mechanism design without money
KW - social choice
UR - http://www.scopus.com/inward/record.url?scp=80051573389&partnerID=8YFLogxK
U2 - https://doi.org/10.1145/2000378.2000390
DO - https://doi.org/10.1145/2000378.2000390
M3 - منشور من مؤتمر
SN - 9781450307079
T3 - ACM International Conference Proceeding Series
SP - 101
EP - 110
BT - TARK XIII
Y2 - 12 July 2011 through 14 July 2011
ER -