Lindeloef in versus in Lindeloef

摘要

A space C is said to be Lindelof in a space Z if every open cover of Z has acountable subcover of X. Arhangelskii asks if there must always be a Lindelof Y with X included in Y included in Z. The authors answer this in the negative. (Copyright (c) 1991 by Faculty of Technical Mathematics and Informatics, Delft, The Netherlands.)