中文

Decisive creatures and large continuum

逻辑 2011-01-25 v2

摘要

For f,gω\hof,g\in\omega\ho let \mycfaf,g\mycfa_{f,g} be the minimal number of uniform gg-splitting trees needed to cover the uniform ff-splitting tree, i.e. for every branch ν\nu of the ff-tree, one of the gg-trees contains ν\nu. \mycf,g\myc_{f,g} is the dual notion: For every branch ν\nu, one of the gg-trees guesses ν(m)\nu(m) infinitely often. It is consistent that \mycfϵ,gϵ=\mycfafϵ,gϵ=κϵ\myc_{f_\epsilon,g_\epsilon}=\mycfa_{f_\epsilon,g_\epsilon}=\kappa_\epsilon for \al1\al1 many pairwise different cardinals κϵ\kappa_\epsilon and suitable pairs (fϵ,gϵ)(f_\epsilon,g_\epsilon). For the proof we use creatures with sufficient bigness and halving. We show that the lim-inf creature forcing satisfies fusion and pure decision. We introduce decisiveness and use it to construct a variant of the countable support iteration of such forcings, which still satisfies fusion and pure decision.

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引用

@article{arxiv.math/0601083,
  title  = {Decisive creatures and large continuum},
  author = {Jakob Kellner and Saharon Shelah},
  journal= {arXiv preprint arXiv:math/0601083},
  year   = {2011}
}

备注

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