Nuprl Lemma : e-union_wf

∀[A,B:EType].  (e-union(A;B) ∈ EType)


Proof




Definitions occuring in Statement :  e-union: e-union(A;B),  e-type: EType,  uall: ∀[x:A]. B[x],  member: t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  e-type: EType,  quotient: x,y:A//B[x; y],  and: P ∧ Q,  e-union: e-union(A;B),  so_lambda: λ2x y.t[x; y],  subtype_rel: A ⊆r B,  prop: ℙ,  so_apply: x[s1;s2],  uimplies: b supposing a,  all: ∀x:A. B[x],  implies: P ⇒ Q,  ext-eq: A ≡ B,  b-union: A ⋃ B,  tunion: ⋃x:A.B[x],  bool: 𝔹,  unit: Unit,  ifthenelse: if b then t else f fi ,  pi2: snd(t)
Lemmas referenced :  e-type_wf,  quotient-member-eq,  ext-eq_wf,  ext-eq-equiv,  b-union_wf,  subtype_rel_b-union-left,  subtype_rel_b-union-right
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation_alt,  cut,  sqequalHypSubstitution,  pointwiseFunctionalityForEquality,  introduction,  extract_by_obid,  hypothesis,  sqequalRule,  pertypeElimination,  productElimination,  thin,  instantiate,  isectElimination,  universeEquality,  lambdaEquality_alt,  hypothesisEquality,  applyEquality,  cumulativity,  inhabitedIsType,  equalityTransitivity,  equalitySymmetry,  independent_isectElimination,  dependent_functionElimination,  independent_functionElimination,  productIsType,  equalityIsType4,  because_Cache,  universeIsType,  independent_pairFormation,  imageElimination,  unionElimination,  equalityElimination

Latex:
\mforall{}[A,B:EType].    (e-union(A;B)  \mmember{}  EType)



Date html generated: 2020_05_20-AM-08_24_38
Last ObjectModification: 2018_10_12-PM-00_37_39

Theory : lattices


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