Topological-like notions via Δ-open sets

Abstract

We provide a characterization of Δ-open and Δ-closed sets in topological spaces. Besides, based on the concepts of Δ-open and Δ-closed sets we investigate the notions of Δ-interior, Δ-exterior, Δ-closure, Δ-derived sets, Δ-boundary sets, and Δ-dense sets. Moreover, we study Δ-open and Δ-closed sets in product topology and subspace typology.