Meaning of closure operator | Babel Free

Definitions

A function which maps any subset X of S onto another such subset (or possibly X itself) called the closure of X (thus providing a mathematical means to define closure).

Equivalents

Examples

“1997 [Kluwer Academic], R. Friĉ, History of Sequential Convergence Spaces, C. E. Aull, R. Lowen (editors), Handbook of the History of General Topology, Volume 1, Springer, page 346, Let u be a closure operator on X satisfying the first three closure axioms: u(U∪B)=uU∪uB,A⊂u(A),u empty = empty .”

CEFR level