摘要: Successors of singular cardinals are a peculiar—although they successor cardinals, can still exhibit some the behaviors typically associated with large cardinals. In this chapter, we examine combinatorics successors in detail. We use stationary reflection as our point entry into subject, and sketch Magidor’s proof that it is consistent all subsets such cardinal reflect. Further consideration brings us to Shelah’s ideal I[λ] related Approachability Property (AP); give fairly comprehensive treatment these topics. Building on this, then turn squares, scales, influence objects exert questions pertaining phenomena. The chapter concludes brief look at square-brackets partition relations their relation club-guessing principles.