Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Consider a society with two sectors (issues or objects) that faces a design problem. Suppose that the sector-2 dimension of the design problem is fixed and represented by a mechanism Γ2, and that the designer operates under this constraint for institutional reasons. A sector-1 mechanism Γ1 constrained implements a social choice rule φ in Nash equilibrium if for each profile of agents' preferences, the set of (pure) Nash equilibrium outcomes of the mechanism Γ1×Γ2 played by agents with those preferences always coincides with the recommendations made by φ for that profile. If this mechanism design exercise could be accomplished, φ would be constrained implementable. We show that constrained monotonicity, a strengthening of (Maskin) monotonicity, is a necessary condition for constrained implementation. When there are more than two agents, and when the designer can use the private information elicited from agents via Γ2 to make a socially optimal decision for sector 1, constrained monotonicity, combined with an auxiliary condition, is sufficient. This sufficiency result does not rule out any kind of complementarity between the two sectors.