In this paper,we first introduce the brief history of the development of band group acting manifolds,the background of the development of L-S category and the related concepts expressed by its fundamental inequality.Secondly,Secondly,We discuss the L-S category(minimal open coverage)of toric manifolds and quasi-torus manifolds M2n,and the conclusion is proved:L-S(Mn·)=L-S(M2n)=n,(n≠0).Thirdly,we give the classification of two-dimensional closed surfaces,and we get the conclusion for any closed surface nT2 and mP2:L-S(nT2)=L-S(mP2)=3,(n,m≥1)and the conclusion is elaborated and proved in detail.Finally,we geometrically construct the minimal open covering of closed any surfaces. |