Ladder gaps over stationary sets

dc.creatorAbraham, Uri
dc.creatorShelah, Saharon
dc.date2004-04-07
dc.date.accessioned2026-07-07T05:07:14Z
dc.date.available2026-07-07T05:07:14Z
dc.descriptionFor a stationary set S subseteq omega_1 and a ladder system C over S, a new type of gaps called C-Hausdorff is introduced and investigated. We describe a forcing model of ZFC in which, for some stationary set S, for every ladder C over S, every gap contains a subgap that is C-Hausdorff. But for every ladder E over omega_1 setminus S there exists a gap with no subgap that is E-Hausdorff. A new type of chain condition, called polarized chain condition, is introduced. We prove that the iteration with finite support of polarized c.c.c posets is again a polarized c.c.c poset.
dc.identifierhttps://arxiv.org/abs/math/0404151
dc.identifierhttp://arxiv.org/abs/math/0404151
dc.identifierJ. Symbolic Logic 69 No. 2 (2004) 518--532
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/70783
dc.subjectLogic
dc.titleLadder gaps over stationary sets
dc.typetext

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