LOCAL FUNCTION Γ * IN IDEAL TOPOLOGICAL SPACES
AHMAD AL-OMARI(1) AND TAKASHI NOIRI(2)
1. Al al-Bayt University, Faculty of Sciences, Department of Mathematics P.O. Box 130095, Mafraq 25113, JORDAN, e-mail: omarimutah1@yahoo.com 2. 2949-1 Shiokita-cho, Hinagu, Yatsushiro-shi, Kumamoto-ken, 869- 5142 JAPAN, e-mail: t.noiri@nifty.com
Abstract
Let (X, τ, I) be an ideal topological space. For a subset A of X, a local function Γ*(A)(I, τ ) is defined as follows: Γ *(A)(I, τ ) = {x in X : A ∩ U not in I, for every regular open set U containing x}. This coincides with the δ-local functions due to Hatir et al. [2]. By using Γ* (A)(I, τ ), an operator Ψ_Γ* : P(X) → τ ^δ is defined as the dual of the δ-local func-tion and its relations with δ-codense ideals are investigated.