Last-modified: 2011-08-20 (土) 17:24:55
- A subset U of X is called β-open if U ⊂ cl(int(cl(U))).
- Basu, C. K.; Afsan, B. M. Uzzal; Ghosh, M. K., A class of functions and separation axioms with respect to an operation. (English summary), Hacet. J. Math. Stat. 38 (2009), no. 2, 103-118.