Title
Welfare Maximization with Friends-of-Friends Network Externalities.
Abstract
Online social networks allow the collection of large amounts of data about the influence between users connected by a friendship-like relationship. When distributing items among agents forming a social network, this information allows us to exploit network externalities that each agent receives from his neighbors that get the same item. In this paper we consider Friends-of-Friends (2-hop) network externalities, i.e., externalities that not only depend on the neighbors that get the same item but also on neighbors of neighbors. For these externalities we study a setting where multiple different items are assigned to unit-demand agents. Specifically, we study the problem of welfare maximization under different types of externality functions. Let be the number of agents and be the number of items. Our contributions are the following: (1) We show that welfare maximization is -hard; we show that even for step functions with 2-hop (and also with 1-hop) externalities it is -hard to approximate social welfare better than (1−1/). (2) On the positive side we present (i) an -approximation algorithm for general concave externality functions, (ii) an (log )-approximation algorithm for linear externality functions, and (iii) a -approximation algorithm for 2-hop step function externalities. We also improve the result from [] for 1-hop step function externalities by giving a -approximation algorithm.
Year
DOI
Venue
2017
10.1007/s00224-017-9759-8
Theory Comput. Syst.
Keywords
DocType
Volume
Network externalities,Welfare maximization,Approximation algorithms,Social networks
Journal
61
Issue
ISSN
Citations 
4
1432-4350
2
PageRank 
References 
Authors
0.36
19
4
Name
Order
Citations
PageRank
Sayan Bhattacharya118219.71
Wolfgang Dvorák227124.57
Monika Rauch Henzinger34307481.86
Martin Starnberger4243.23