A dichotomy on Schreier sets
Studia Mathematica, Tome 132 (1999) no. 3, pp. 245-256
Cet article a éte moissonné depuis la source Institute of Mathematics Polish Academy of Sciences
We show that the Schreier sets $S_α(α ω_1)$ have the following dichotomy property. For every hereditary collection ℱ of finite subsets of ℱ, either there exists infinite $M = (m_i)_{i=1}^∞ ⊆ ℕ$ such that $S_α(M)={{m_i:i ∈ E}: E ∈ S_α} ⊆ ℱ$, or there exist infinite $M = (m_i)_{i=1}^∞, N ⊆ ℕ$ such that $ℱ[N](M) = {{m_i:i ∈ F}:F ∈ ℱ and F ⊂ N } ⊆ S_α$.
@article{10_4064_sm_132_3_245_256,
author = {Robert Judd},
title = {A dichotomy on {Schreier} sets},
journal = {Studia Mathematica},
pages = {245--256},
year = {1999},
volume = {132},
number = {3},
doi = {10.4064/sm-132-3-245-256},
language = {de},
url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-132-3-245-256/}
}
Robert Judd. A dichotomy on Schreier sets. Studia Mathematica, Tome 132 (1999) no. 3, pp. 245-256. doi: 10.4064/sm-132-3-245-256
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