Paths, Cycles and Mechanism Design

The incentive compatibility constraints of mechanism design (with quasi-linear utilities) can be interpreted as being the dual inequalities of a shortest path problem. I believe this interpretation provides an intuitive and powerful lens through which to view the implications of incentive compatibility. This document provides an (incomplete) account of the main results in mechanism design from this point of view. They assume familiarity with mechanism design and basic linear programming and convex analysis. I welcome suggestions for additions, deletions and improvements to this material.