Strategy-proof location of public facilities

Consider the problem of locating a public facility taking into account the agents' preferences. To construct strategy-proof social choice rules, we propose a new preference domain that allows agents to have any single-peaked or any single-dipped preference on the location of the facility such that the peak/dip of the preference is in her own location. We characterize all strategy-proof rules in this general framework and study the conditions under which this family of strategy-proof rules includes non-dictatorial rules that have more than two alternatives in the range or that are Pareto efficient. Finally, we characterize for some focal cases all strategy-proof and Pareto efficient rules.