Alexander's subbase theorem
Alexander's subbase theorem
[‚al·ig′zan·dərz ¦səb‚bās ‚thir·əm] (mathematics)
The theorem that a topological space is compact if and only if its topology has a subbase with the property that any set that is contained in the union of a collection of members of the subbase is contained in the union of a finite number of members of this collection.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.