2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/77643This paper covers some recent progress in the study of sg-open sets, sg-compact spaces, N-scattered spaces and some related concepts. A subset $A$ of a topological space $(X,τ)$ is called sg-closed if the semi-closure of $A$ is included in every semi-open superset of $A$. Complements of sg-closed sets are called sg-open. A topological space $(X,τ)$ is called sg-compact if every cover of $X$ by sg-open sets has a finite subcover. N-scattered space is a topological spaces in which every nowhere dense subset is scattered.14 pages, Presented at the 1997 Yatsushiro Topological Conference, 23-24 August 1997, JapanGeneral Topology54-06; 54D30; 54G12; 54A05; 54H05; 54G99text