Nuprl Lemma : compact-union
∀[T,S:Type].  (compact-type(T) ⇒ compact-type(S) ⇒ compact-type(T + S))
Proof
Definitions occuring in Statement : 
compact-type: compact-type(T), 
uall: ∀[x:A]. B[x], 
implies: P ⇒ Q, 
union: left + right, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
implies: P ⇒ Q, 
compact-type: compact-type(T), 
all: ∀x:A. B[x], 
member: t ∈ T, 
prop: ℙ, 
or: P ∨ Q, 
exists: ∃x:A. B[x], 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
guard: {T}, 
squash: ↓T, 
true: True, 
subtype_rel: A ⊆r B, 
uimplies: b supposing a, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
rev_implies: P ⇐ Q
Lemmas referenced : 
bool_wf, 
compact-type_wf, 
equal-wf-T-base, 
all_wf, 
equal_wf, 
squash_wf, 
true_wf, 
btrue_wf, 
iff_weakening_equal, 
exists_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
sqequalHypSubstitution, 
functionEquality, 
unionEquality, 
cumulativity, 
hypothesisEquality, 
cut, 
introduction, 
extract_by_obid, 
hypothesis, 
isectElimination, 
thin, 
universeEquality, 
dependent_functionElimination, 
lambdaEquality, 
applyEquality, 
functionExtensionality, 
inlEquality, 
sqequalRule, 
unionElimination, 
productElimination, 
inlFormation, 
dependent_pairFormation, 
baseClosed, 
inrEquality, 
inrFormation, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
natural_numberEquality, 
imageMemberEquality, 
independent_isectElimination, 
independent_functionElimination, 
because_Cache
Latex:
\mforall{}[T,S:Type].    (compact-type(T)  {}\mRightarrow{}  compact-type(S)  {}\mRightarrow{}  compact-type(T  +  S))
Date html generated:
2017_10_01-AM-08_29_00
Last ObjectModification:
2017_07_26-PM-04_23_46
Theory : basic
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