Strong Equilibrium in Cost-Sharing Connection Game
Amir Epstein, Michal Feldman and Yishay Mansour
In: The Eighth ACM Conference on Electronic Commerce 2007, June 8-16, 2007, San Diego, CA, USA.
In this work we study cost sharing connection games, where
each player has a source and sink he would like to connect,
and the cost of the edges is either shared equally (fair con-
nection games) or in an arbitrary way (general connection
games). We study the graph topologies that guarantee the
existence of a strong equilibrium (where no coalition can
improve the cost of each of its members) regardless of the
speci¯c costs on the edges.
Our main existence results are the following: (1) For a
single source and sink we show that there is always a strong
equilibrium (both for fair and general connection games).
(2) For a single source multiple sinks we show that for a
series parallel graph a strong equilibrium always exists (both
for fair and general connection games). (3) For multi source
and sink we show that an extension parallel graph always
admits a strong equilibrium in fair connection games.
As for the quality of the strong equilibrium we show that
in any fair connection games the cost of a strong equilibrium
is £(log n) from the optimal solution, where n is the number
of players. (This should be contrasted with the (n) price
of anarchy for the same setting.) For single source general
connection games and single source single sink fair connec-
tion games, we show that a strong equilibrium is always an
|EPrint Type:||Conference or Workshop Item (Paper)|
|Project Keyword:||Project Keyword UNSPECIFIED|
|Subjects:||Theory & Algorithms|
|Deposited By:||Yishay Mansour|
|Deposited On:||20 May 2007|