Date of Original Version
© 2010 Association for Symbolic Logic
Abstract or Description
It is a well-known phenomenon in set theory that problems in in- finite combinatorics involving singular cardinals and their successors tend to be harder than the parallel problems for regular cardinals. Examples include the behaviour of cardinal exponentiation, the extent of the tree property, the extent of stationary reflection, and the existence of non-free almost-free abelian groups. The explanation for this phenomenon lies in inner model theory, in particular core models and covering lemmas.
Journal of Symbolic Logic, 75, 4, 1383-1402.