English

Few new reals

Logic 2023-03-22 v7

Abstract

We introduce a new method for building models of CH, together with Π2\Pi_2 statements over H(ω2)H(\omega_2), by forcing. Unlike other forcing constructions in the literature, our construction adds new reals, although only 1\aleph_1-many of them. Using this approach, we build a model in which a very strong form of the negation of Club Guessing at ω1\omega_1 known as Measuring holds together with CH, thereby answering a well-known question of Moore. This construction can be described as a finite-support weak forcing iteration with side conditions consisting of suitable graphs of sets of models with markers. The CH-preservation is accomplished through the imposition of copying constraints on the information carried by the condition, as dictated by the edges in the graph.

Keywords

Cite

@article{arxiv.1712.07724,
  title  = {Few new reals},
  author = {David Aspero and Miguel Angel Mota},
  journal= {arXiv preprint arXiv:1712.07724},
  year   = {2023}
}

Comments

39 pages

R2 v1 2026-06-22T23:25:17.478Z