Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
In a model with finitely many agents who have single-dipped Euclidean preferences on a disc in the Euclidean plane, a rule assigns to each profile of reported dips a point of the disc. It is proved that any strategy-proof and Pareto optimal rule is dictatorial. This framework models situations where public bads such as garbage dumping grounds or nuclear plants have to be located within a confined region that has the shape of a disc.