Additively-separable and rank-discounted variable-population social welfare functions: A characterization

A sufficient condition for additively separable functions

Additively separable functions on RN are of the form I;= 1 Ui(Xi). These functions have the obvious property that they are completely separable. That is, the induced orders on the (N 1)-dimensional sets {(x,, . . . , xN): xi0 = c} are independent of c. A natural question is whether the opposite is also true, that is, whether complete separability of a function V implies additive separability. D...

Escaping the repugnant conclusion: Rank-discounted utilitarianism with variable population

We contribute to population ethics by proposing and axiomatizing rankdiscounted critical-level generalized utilitarianism (RDCLU). Population ethics is needed for evaluation of policies, e.g., concerning climate change, where population size depends on the chosen policy. We show that critical-level generalized utilitarianism and (a version of) critical-level leximin are the limits of RDCLU for ...

Quadratic Social Welfare Functions

Justifying social discounting: The rank-discounted utilitarian approach

The discounted utilitarian criterion for infinite horizon social choice has been criticized for treating generations unequally. We propose an extended rank-discounted utilitarian (ERDU) criterion instead. The criterion amounts to discounted utilitarianism on non-decreasing streams, but it treats all generations impartially: discounting becomes the mere expression of intergenerational inequality...

Optimal Partitions in Additively Separable Hedonic Games

We conduct a computational analysis of partitions in additively separable hedonic games that satisfy standard criteria of fairness and optimality. We show that computing a partition with maximum egalitarian or utilitarian social welfare is NP-hard in the strong sense whereas a Pareto optimal partition can be computed in polynomial time when preferences are strict. Perhaps surprisingly, checking...