English

L(R) absoluteness under proper forcings

Logic 2007-05-23 v1

Abstract

We isolate a new large cardinal concept, "remarkability." Consistencywise, remarkable cardinals are between ineffable and omega-Erdos cardinals. They are characterized by the existence of "0^sharp-like" embeddings; however, they relativize down to L. It turns out that the existence of a remarkable cardinal is equiconsistent with L(R) absoluteness under proper forcings. In particular, said absoluteness does not imply Pi^1_1 determinacy.

Keywords

Cite

@article{arxiv.math/9909043,
  title  = {L(R) absoluteness under proper forcings},
  author = {Ralf Schindler},
  journal= {arXiv preprint arXiv:math/9909043},
  year   = {2007}
}

Comments

15 pages

R2 v1 2026-07-22T18:04:25.664Z