Lusternik-Schnirelmann cocategory
Lusternik-Schnirelmann cocategory
IntroductionIn the last ten years there has been a revival of interest in the (Lusternik- Schnirelmann) category of a topological space X.Recall the classical defini- tion: a space X has category < n if and only if it can be covered by n + 1 open sets, each of which …