Nuprl Lemma : open-isect_wf

∀[X:Type]. ∀[A,B:Open(X)].  (open-isect(A;B) ∈ Open(X))


Proof




Definitions occuring in Statement :  open-isect: open-isect(A;B),  Open: Open(X),  uall: ∀[x:A]. B[x],  member: t ∈ T,  universe: Type
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  open-isect: open-isect(A;B),  Open: Open(X),  subtype_rel: A ⊆r B
Lemmas referenced :  sp-meet_wf,  Sierpinski_wf,  Open_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  sqequalRule,  lambdaEquality,  lemma_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  applyEquality,  hypothesisEquality,  hypothesis,  functionEquality,  axiomEquality,  equalityTransitivity,  equalitySymmetry,  isect_memberEquality,  because_Cache,  universeEquality

Latex:
\mforall{}[X:Type].  \mforall{}[A,B:Open(X)].    (open-isect(A;B)  \mmember{}  Open(X))



Date html generated: 2019_10_31-AM-07_18_50
Last ObjectModification: 2015_12_28-AM-11_20_57

Theory : synthetic!topology


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