 
Summary: Truthful Mechanisms for OneParameter Agents
Aaron Archer \Lambda ’
Eva Tardos y
Abstract
In this paper, we show how to design truthful (dominant
strategy) mechanisms for several combinatorial problems
where each agent's secret data is naturally expressed by a
single positive real number. The goal of the mechanisms
we consider is to allocate loads placed on the agents, and
an agent's secret data is the cost she incurs per unit load.
We give an exact characterization for the algorithms that
can be used to design truthful mechanisms for such load
balancing problems using appropriate side payments.
We use our characterization to design polynomial time
truthful mechanisms for several problems in combinato
rial optimization to which the celebrated VCG mechanism
does not apply. For scheduling related parallel machines
(QjjC max ), we give a 3approximation mechanism based
on randomized rounding of the optimal fractional solution.
This problem is NPcomplete, and the standard approxima
