Last-modified: 2010-11-12 (金) 18:23:21
Let A be a subset of a topological space X.
By we denote the set (see semi-θ-closed).
A is called -set if .
A is called (Λ,sθ)-closed (or -semi-θ-closed) if A=T∩C for some -set T and some semi-θ-closed set C.
The complement of a (Λ,sθ)-closed set is called (Λ,sθ)-open (or -semi-θ-open).
M. Caldas, M. Ganster, D. N. Georgiou, S. Jafari, V. Popa, On a Generalization of Closed Sets, Kyungpook Math. J. 47(2007), 155-164.