Nuprl Lemma : ite_wf
∀[b:𝔹]. ∀[T:Type]. ∀[x:T supposing ↑b]. ∀[y:T supposing ¬↑b].  (ite(b;x;y) ∈ T)
Proof
Definitions occuring in Statement : 
ite: ite(b;x;y), 
assert: ↑b, 
bool: 𝔹, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
not: ¬A, 
member: t ∈ T, 
universe: Type
Definitions unfolded in proof : 
ite: ite(b;x;y), 
bool: 𝔹, 
assert: ↑b, 
ifthenelse: if b then t else f fi , 
member: t ∈ T, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
prop: ℙ, 
true: True, 
not: ¬A, 
implies: P ⇒ Q, 
false: False
Lemmas referenced : 
not_wf, 
assert_wf, 
bool_wf, 
false_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
sqequalHypSubstitution, 
unionElimination, 
thin, 
sqequalRule, 
isectEquality, 
cut, 
lemma_by_obid, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
because_Cache, 
universeEquality, 
isect_memberFormation, 
introduction, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
isect_memberEquality, 
independent_isectElimination, 
natural_numberEquality, 
lambdaEquality, 
voidElimination, 
lambdaFormation
Latex:
\mforall{}[b:\mBbbB{}].  \mforall{}[T:Type].  \mforall{}[x:T  supposing  \muparrow{}b].  \mforall{}[y:T  supposing  \mneg{}\muparrow{}b].    (ite(b;x;y)  \mmember{}  T)
Date html generated:
2016_05_15-PM-03_26_22
Last ObjectModification:
2015_12_27-PM-01_07_25
Theory : general
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