More set-theory around the weak Freese–Nation property
Fundamenta Mathematicae, Tome 154 (1997) no. 2, pp. 159-176
Cet article a éte moissonné depuis la source Institute of Mathematics Polish Academy of Sciences
We introduce a very weak version of the square principle which may hold even under failure of the generalized continuum hypothesis. Under this weak square principle, we give a new characterization (Theorem 10) of partial orderings with κ-Freese-Nation property (see below for the definition). The characterization is not a ZFC theorem: assuming Chang's Conjecture for $ℵ_ω$, we can find a counter-example to the characterization (Theorem 12). We then show that, in the model obtained by adding Cohen reals, a lot of ccc complete Boolean algebras of cardinality ≤ λ have the $ℵ_1$-Freese-Nation property provided that $μ^{ℵ_0} = μ$ holds for every regular uncountable μ λ and the very weak square principle holds for each cardinal $ℵ_0 μ λ$ of cofinality ω ((Theorem 15). Finally, we prove that there is no $ℵ_2$-Lusin gap if P(ω) has the $ℵ_1$-Freese-Nation property (Theorem 17)
@article{10_4064_fm_154_2_159_176,
author = {Saka\'e Fuchino and Lajos Soukup},
title = {More set-theory around the weak {Freese{\textendash}Nation} property},
journal = {Fundamenta Mathematicae},
pages = {159--176},
year = {1997},
volume = {154},
number = {2},
doi = {10.4064/fm-154-2-159-176},
language = {en},
url = {http://geodesic.mathdoc.fr/articles/10.4064/fm-154-2-159-176/}
}
TY - JOUR AU - Sakaé Fuchino AU - Lajos Soukup TI - More set-theory around the weak Freese–Nation property JO - Fundamenta Mathematicae PY - 1997 SP - 159 EP - 176 VL - 154 IS - 2 UR - http://geodesic.mathdoc.fr/articles/10.4064/fm-154-2-159-176/ DO - 10.4064/fm-154-2-159-176 LA - en ID - 10_4064_fm_154_2_159_176 ER -
Sakaé Fuchino; Lajos Soukup. More set-theory around the weak Freese–Nation property. Fundamenta Mathematicae, Tome 154 (1997) no. 2, pp. 159-176. doi: 10.4064/fm-154-2-159-176
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