Mathematical logic quarterly · 1998 · 14 citations · 8 references
Natural SciencesMathematicsSet TheoryAxiom Of ChoiceAxiomatic Set TheoryCombinatorial Set TheorySet-theoretic TopologyDisjoint SetsNormality AxiomsSet-theoretic Consequences Of ChoiceTietze Extension TheoremUrysohn LemmaWeak Forms
Abstract We investigate the set theoretical strength of some properties of normality, including Urysohn's Lemma, Tietze‐Urysohn Extension Theorem, normality of disjoint unions of normal spaces, and normality of F σ subsets of normal spaces.
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Continuing horrors of topology without choice
Chris Good, I.J. Tree · Topology and its Applications · 1995 · 85 citations
Amit Levy · Fundamenta Mathematicae · 1962 · 57 citations · Full text
Business, Mathematics, Logic +7