Abstract
The depth of a topological space X (g(X)) is defined as the supremum of the cardinalities of closures of discrete subsets of X. Solving a problem of Martínez-Ruiz, Ramírez-Páramo and Romero-Morales, we prove that the cardinal inequality |X|≤g(X)L(X)⋅F(X) holds for every Hausdorff space X, where L(X) is the Lindelöf number of X and F(X) is the supremum of the cardinalities of the free sequences in X.
Lingua originale | English |
---|---|
Numero di pagine | 5 |
Rivista | Quaestiones Mathematicae |
Stato di pubblicazione | Published - 2019 |
All Science Journal Classification (ASJC) codes
- ???subjectarea.asjc.2600.2601???