*Definition [#ya67208e]
-For any free [[ultrafilter]] D on Ｎ, a topological space X is called D-feebly compact if for every sequence &ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20%5c%7bU_n:n%5cin%5cmathbb%7bN%7d%5c%7d%20%5c%5d%7d%25.png); of nonempty open subsets of X there is a point p in X such that for every neighbourhood V of p, &ref(http://www.eaflux.com/imgtex/imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20%5c%7bn:V%5ccap%20U_n%5cneq%5cemptyset%5c%7d%5cin%5cmathcal%7bD%7d%20%5c%5d%7d%25.png);

*Reference [#g3ec1848]
-''Encyclopedia of general topology'', Edited by Klaas Pieter Hart, Jun-iti Nagata and Jerry E. Vaughan. Elsevier Science Publishers, B.V., Amsterdam, 2004.