Nuprl Lemma : tunion-value-type
∀[A:Type]. ∀[B:A ⟶ Type].  value-type(⋃a:A.B[a]) supposing ∀a:A. value-type(B[a])
Proof
Definitions occuring in Statement : 
value-type: value-type(T), 
uimplies: b supposing a, 
tunion: ⋃x:A.B[x], 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
all: ∀x:A. B[x], 
function: x:A ⟶ B[x], 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
value-type: value-type(T), 
sq_stable: SqStable(P), 
implies: P ⇒ Q, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
all: ∀x:A. B[x], 
tunion: ⋃x:A.B[x], 
has-value: (a)↓, 
top: Top, 
pi1: fst(t), 
prop: ℙ, 
squash: ↓T, 
guard: {T}
Lemmas referenced : 
sq_stable__has-value, 
tunion_wf, 
value-type-has-value, 
pi1_wf, 
pi2_wf, 
top_wf, 
equal_wf, 
equal-wf-base, 
base_wf, 
all_wf, 
value-type_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
independent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
cumulativity, 
sqequalRule, 
lambdaEquality, 
applyEquality, 
functionExtensionality, 
lambdaFormation, 
imageElimination, 
productElimination, 
dependent_pairEquality, 
independent_isectElimination, 
independent_pairEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
productEquality, 
dependent_functionElimination, 
imageMemberEquality, 
baseClosed, 
because_Cache, 
axiomSqleEquality, 
functionEquality, 
universeEquality
Latex:
\mforall{}[A:Type].  \mforall{}[B:A  {}\mrightarrow{}  Type].    value-type(\mcup{}a:A.B[a])  supposing  \mforall{}a:A.  value-type(B[a])
 Date html generated: 
2017_04_14-AM-07_15_02
 Last ObjectModification: 
2017_02_27-PM-02_50_33
Theory : call!by!value_1
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