Define interior point in metric space
1
Let (X, d) be a metric space and A be a subset of X. then a point x ∈ X is called an interior point of A iff A is a neighborhood of x.
2
Let (X, d) be a metric space and A be a subset of A. then a point x ∈ X is called an interior point of A iff A is a neighborhood of x.
3
Let (X, d) be a metric space and A be a subset of X. then a point x ∈ X is called an interior point of A iff A is not a neighborhood of x.
4
Let (X, d) be a metric space and A be a subset of X. then a point x ∈ X is called an interior point of A iff A is a deleted neighborhood of x.