Given an ordinal , a subset of is called a club if it is closed in the order topology of but has net-theoretic limit . The clubs of form a filter: the club filter, .
given an oRdInal , a SUbseT OF iS CAlLed A CLuB if IT is cLosed iN the ORdeR topology oF but has net-theoRetic limit . the CLubs of foRm a filter: tHe Club filter, .