Higher Gap Morasses, IA: Gap-Two Morasses and Condensation
Abstract
This paper concerns the theory of morasses. In the early 1970s Jensen defined -morasses for uncountable regular cardinals $\kappa$ and ordinals $\alpha < \kappa$. In the early 1980s Velleman defined -simplified morasses for all regular cardinals $\kappa$. He showed that there is a -simplified morass if and only if there is -morass. More recently he defined -simplified morasses and Jensen was able to show that if there is a -morass then there is a -simplified morass. In this paper we prove the converse of Jensen's result, i.e., that if there is a -simplified morass then there is a -morass.