TY - GEN

T1 - Path deviations outperform approximate stability in heterogeneous congestion games

AU - Kleer, Pieter

AU - Schäfer, Guido

PY - 2017/1/1

Y1 - 2017/1/1

N2 - We consider non-atomic network congestion games with heterogeneous players where the latencies of the paths are subject to some bounded deviations. This model encompasses several well-studied extensions of the classical Wardrop model which incorporate, for example, risk-aversion, altruism or travel time delays. Our main goal is to analyze the worst-case deterioration in social cost of a deviated Nash flow (i.e., for the perturbed latencies) with respect to an original Nash flow. We show that for homogeneous players deviated Nash flows coincide with approximate Nash flows and derive tight bounds on their inefficiency. In contrast, we show that for heterogeneous populations this equivalence does not hold. We derive tight bounds on the inefficiency of both deviated and approximate Nash flows for arbitrary player sensitivity distributions. Intuitively, our results suggest that the negative impact of path deviations (e.g., caused by risk-averse behavior or latency perturbations) is less severe than approximate stability (e.g., caused by limited responsiveness or bounded rationality). We also obtain a tight bound on the inefficiency of deviated Nash flows for matroid congestion games and homogeneous populations if the path deviations can be decomposed into edge deviations. In particular, this provides a tight bound on the Price of Risk-Aversion for matroid congestion games.

AB - We consider non-atomic network congestion games with heterogeneous players where the latencies of the paths are subject to some bounded deviations. This model encompasses several well-studied extensions of the classical Wardrop model which incorporate, for example, risk-aversion, altruism or travel time delays. Our main goal is to analyze the worst-case deterioration in social cost of a deviated Nash flow (i.e., for the perturbed latencies) with respect to an original Nash flow. We show that for homogeneous players deviated Nash flows coincide with approximate Nash flows and derive tight bounds on their inefficiency. In contrast, we show that for heterogeneous populations this equivalence does not hold. We derive tight bounds on the inefficiency of both deviated and approximate Nash flows for arbitrary player sensitivity distributions. Intuitively, our results suggest that the negative impact of path deviations (e.g., caused by risk-averse behavior or latency perturbations) is less severe than approximate stability (e.g., caused by limited responsiveness or bounded rationality). We also obtain a tight bound on the inefficiency of deviated Nash flows for matroid congestion games and homogeneous populations if the path deviations can be decomposed into edge deviations. In particular, this provides a tight bound on the Price of Risk-Aversion for matroid congestion games.

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U2 - 10.1007/978-3-319-66700-3_17

DO - 10.1007/978-3-319-66700-3_17

M3 - Conference contribution

AN - SCOPUS:85029377743

SN - 9783319666990

T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

SP - 212

EP - 224

BT - Algorithmic Game Theory - 10th International Symposium, SAGT 2017, Proceedings

A2 - Bilo, Vittorio

A2 - Flammini, Michele

PB - Springer Verlag

T2 - 10th International Symposium on Algorithmic Game Theory, SAGT 2017

Y2 - 12 September 2017 through 14 September 2017

ER -