A topological space X is said to
have the disappearing closed set (DCS) property or to be a DCS space, if for
every proper closed subset C there is a family of open sets {Ui}i=1∞ such
that Ui+1⊆ Ui and ⋂i=1∞Ui= ∅, and there is also a sequence {hi} of
homeomorphisms on X onto X such that hi(C) ⊆ Ui, for all i. Properties of
DCS spaces are studied as are connections between this and other related
definitions.