Definition
- A subset S of a topological space (X,τ) is called a semi-Difference set (in short pD-set) if there are two pre-open? sets U, V in X such that .
Reference
- Athisaya Ponmani, S.; Lellis Thivagar, M., Another form of separation axioms. , (English) [J] Methods Funct. Anal. Topol. 13, No. 4, 380-385 (2007).