2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/77808The aim of this paper is introduce and initiate the study of extremally $T_1$-spaces, i.e., the spaces where all hereditarily compact $C_2$-subspaces are closed. A $C_2$-space is a space whose nowhere dense sets are finite.9 pagesGeneral Topology54D10; 54D30;54A05; 54G99text