Martin's Axiom and Delta21 well-ordering of the reals
Abstract
Assuming an inaccessible cardinal kappa, there is a generic extension in which MA + 2aleph0 = kappa holds and the reals have a Delta21 well-ordering.
0
Turn this paper into a full lesson
ArcXiv compiles a staged curriculum from this paper: 8-12 lessons across beginner → advanced, synthesised section guides, visuals, flashcards, a quiz, exercises, and on-demand deep dives per section. Grounded in the abstract, never invented.