A common extension of Lindelöf, H-closed and ccc

2020/02/07 by Angelo Bella, Bella, Angelo
Computer Science · Decision Sciences · Mathematics · #Advanced Banach Space Theory #Advanced Topology and Set Theory #Constraint Satisfaction and Optimization #FOS: Mathematics #Fuzzy and Soft Set Theory #General Topology (math.GN)

paper · pdf · doi:10.48550/arxiv.2002.02719

openalex publication_date 2020/02/07 · openalex created_date 2022/07/26 · openalex updated_date 2026/07/28

Abstract

The inequality |X| ≤ 2^χ(X) has been proved to be true for Lindelöf spaces (Arhangel'ski\uı, 1969), H-closed spaces (Dow-Porter, 1982) and ccc spaces (Hajnal-Juász 1967), by quite different arguments. We present a common extension of all these properties which allows us to give a unified proof of these three theorems.

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