Definition
- Let S be a subset of a topological space (X, τ). A point x in a topological space (X, τ) is called a λ-cluster point of S if every λ-open set U of X containing x such that .
Reference
- Caldas Miguel, Jafari Saeid, On some low separation axioms via λ-open and λ-closure operator., Rend. Circ. Mat. Palermo (2) 54 (2005), no. 2, 195–208.