We review the relationship between polygyny and HIV and identify a positive individual-level correlation, and a negative ecological correlation. We subsequently examine two mechanisms that contribute to the individual-level correlation. First, we find that men in polygynous marriages have more extramarital sex than men in monogamous unions (both in terms of self reports and in terms of spousal ...

where the variables α and β range over entities of some sort, and where ∼ is an equivalence relation on this sort of entity. Frege’s inconsistent Basic Law V shows that not every such principle is acceptable. A variety of criteria for acceptable abstraction have been proposed.1 In this note I analyze the logical relations between some of the proposed criteria, in particular conservativeness, ir...