Reflection of clubs, and forcing principles at $\aleph_2$
De Itay Neeman
Apparaît dans les collections : 13th International workshop in set theory / 13ème Atelier international de théorie des ensembles, 13th International workshop in set theory / 13ème Atelier international de théorie des ensembles
In 1971 Baumgartner showed it is consistent that any two $\aleph_1$-dense subsets of the real line are order isomorphic. This was important both for the methods of the proof and for consequences of the result. We introduce methods that lead to an analogous result for $\aleph_2$-dense sets.
Keywords : forcing - large cardinals - Baumgartner isomorphism - infinitary Ramsey principles - reflection principles