KnowraTietze extension theoremLinked fromLinked fromThe 5 pages that link to Tietze extension theorem, each with the reason it gives.All 5Related 3Compared with 2Hahn–Banach theoremCompared with: It is a topological analogue involving continuous functions, not linear functionals or norm control.Stone–Čech compactificationCompared with: Unlike extension from a closed subset, βX extends maps from all of X into compact Hausdorff targets.Normal spaceRelated: It is a major consequence of normality for extending functions.Separation axiomRelated: Normality is the separation hypothesis that makes this extension result possible.Urysohn's lemmaRelated: Its proof builds extensions from Urysohn functions that separate closed sets.