Marco Scarsini

interaction seminar

Marco Scarsini

Luiss University
When is selfish routing bad? The price of anarchy in light and heavy traffic
Co-écrit avec
Riccardo Colini-Baldeschi, Roberto Cominetti, Panayotis Mertikopoulos
Lieu

IBD Salle 21

Îlot Bernard du Bois - Salle 21

AMU - AMSE
5-9 boulevard Maurice Bourdet
13001 Marseille

Date(s)
Jeudi 17 mai 2018| 12:00 - 13:15
Contact(s)

Ugo Bolletta : ugo.bolletta[at]univ-amu.fr
Mathieu Faure : mathieu.faure[at]univ-amu.fr

Résumé

This paper examines the behavior of the price of anarchy as a function of the traffic inflow in nonatomic congestion games with multiple origin-destination (O/D) pairs. Empirical studies in real-world networks show that the price of anarchy is close to 1 in both light and heavy traffic, thus raising the question: can these observations be justified theoretically? We first show that this is not always the case: the price of anarchy may remain a positive distance away from 1 for all values of the traffic inflow, even in simple three-link networks with a single O/D pair and smooth, convex costs. On the other hand, for a large class of cost functions (including all polynomials), the price of anarchy does converge to 1 in both heavy and light traffic, irrespective of the network topology and the number of O/D pairs in the network. We also examine the rate of convergence of the price of anarchy, and we show that it follows a power law whose degree can be computed explicitly when the network's cost functions are polynomials.