In this paper, we prove some properties of families of ?-open sets, study the properties of the space of ?-continuous mappings, as well as the properties of the e-density of topological spaces. We prove an analogue of A.V.Arkhangelskii?s theorem for ?-base. Also we showed that the base of a topological space is not always a ?-base. We introduce the notion of e-density of topological spaces. As well as, we investigate some properties of this cardinal function. It is given an example of a topological space, e-density of which is not equal to its density.
Beshimov et al. (Wed,) studied this question.