Lindelöf number
From HandWiki
This category corresponds roughly to MSC {{{id}}} {{{title}}}; see {{{id}}} at MathSciNet and {{{id}}} at zbMATH.
density character
One of the cardinal characteristics of a topological space. The least infinite cardinal number $\tau$ such that every open covering has a subcovering of cardinality at most $\tau$.
References
- Mary Ellen Rudin, Lectures on Set Theoretic Topology, American Mathematical Society (1975) ISBN 0-8218-1673-X
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