Definition
A subset Y of a space X is said to be countably 3-paracompact in X iff for every countable open cover U of X, there exists a collection V which satisfies:
- V consists of open subsets of Y;
- V covers Y;
- V is a partial refinement? of U;
- V is locally finite at Y.
Remark
- See 3-paracompact.
Reference
K.P.Hart, J. Nagata and J.E. Vaughan, Encyclopedia of general topology, Elsevier Science.