densely defined (original) (raw)

Given a topological space X, we say that a map f:Y→X is densely defined if its domain Y is a dense subset of X.

This terminology is commonly used in the of linear operators with the following meaning: In a normed space X, a linear operator A:𝒟⁢(A)⊂X→X is said to be densely defined if 𝒟⁢(A) is a dense vector subspace of X.