Closed subsets of located metric spaces
Content created by Louis Wasserman.
Created on 2025-08-30.
Last modified on 2025-11-15.
module metric-spaces.closed-subsets-located-metric-spaces where
Imports
open import foundation.dependent-pair-types open import foundation.propositions open import foundation.subtypes open import foundation.universe-levels open import metric-spaces.closed-subsets-metric-spaces open import metric-spaces.located-metric-spaces open import metric-spaces.metric-spaces
Idea
A subset S of a
located metric space X is
closed¶
if it is a closed subset of the
underlying metric space
Definition
module _ {l1 l2 l3 : Level} (X : Located-Metric-Space l1 l2) (S : subset-Located-Metric-Space l3 X) where is-closed-prop-subset-Located-Metric-Space : Prop (l1 ⊔ l2 ⊔ l3) is-closed-prop-subset-Located-Metric-Space = is-closed-prop-subset-Metric-Space ( metric-space-Located-Metric-Space X) ( S) is-closed-subset-Located-Metric-Space : UU (l1 ⊔ l2 ⊔ l3) is-closed-subset-Located-Metric-Space = type-Prop is-closed-prop-subset-Located-Metric-Space closed-subset-Located-Metric-Space : {l1 l2 : Level} (l3 : Level) (X : Located-Metric-Space l1 l2) → UU (l1 ⊔ l2 ⊔ lsuc l3) closed-subset-Located-Metric-Space l3 X = closed-subset-Metric-Space l3 (metric-space-Located-Metric-Space X) subset-closed-subset-Located-Metric-Space : {l1 l2 l3 : Level} (X : Located-Metric-Space l1 l2) → (S : closed-subset-Located-Metric-Space l3 X) → subset-Located-Metric-Space l3 X subset-closed-subset-Located-Metric-Space X = pr1 is-closed-subset-closed-subset-Located-Metric-Space : {l1 l2 l3 : Level} (X : Located-Metric-Space l1 l2) → (S : closed-subset-Located-Metric-Space l3 X) → is-closed-subset-Located-Metric-Space ( X) ( subset-closed-subset-Located-Metric-Space X S) is-closed-subset-closed-subset-Located-Metric-Space X = pr2 is-in-closed-subset-Located-Metric-Space : {l1 l2 l3 : Level} (X : Located-Metric-Space l1 l2) → (S : closed-subset-Located-Metric-Space l3 X) → type-Located-Metric-Space X → UU l3 is-in-closed-subset-Located-Metric-Space X S = is-in-subtype (pr1 S)
External links
- Closed set at Wikidata
Recent changes
- 2025-11-15. Louis Wasserman. Every point in a proper closed interval in the real numbers is an accumulation point (#1679).
- 2025-08-30. Louis Wasserman. Topology in metric spaces (#1474).