Definition
Let X be a Tychonoff space, υX the Hewitt-Nachbin realcompactification.
For subset A of X, we write
,
,
.
We say X is λ-compact iff
.
Remark
- cf. realcompact.
Reference
- I.Blum and S.Swaminathan, A note on intersections of ideals in rings of continuous functions, in "Topology", Coloquia Mathematica Societatis Janos Bolyai 23 Vol I, North Holland, Amsterdam, 1980, pp.155-162.
- http://www.utm.edu/staff/jschomme/weakdefs.html