Nuprl Lemma : exists-product3
∀[A,B,C,D:Type].  ∀P:(A × B × C × D) ⟶ ℙ'. {∃x:A × B × C × D. P[x] 
⇐⇒ ∃a:A. ∃b:B. ∃c:C. ∃d:D. P[<a, b, c, d>]}
Proof
Definitions occuring in Statement : 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
guard: {T}
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
function: x:A ⟶ B[x]
, 
pair: <a, b>
, 
product: x:A × B[x]
, 
universe: Type
Definitions unfolded in proof : 
guard: {T}
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
rev_implies: P 
⇐ Q
, 
exists: ∃x:A. B[x]
Lemmas referenced : 
exists_wf, 
exists-product1, 
iff_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
lambdaFormation, 
cut, 
independent_pairFormation, 
hypothesis, 
thin, 
instantiate, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
cumulativity, 
hypothesisEquality, 
lambdaEquality, 
applyEquality, 
independent_pairEquality, 
because_Cache, 
addLevel, 
productElimination, 
independent_functionElimination, 
productEquality, 
dependent_functionElimination, 
existsFunctionality, 
impliesFunctionality, 
levelHypothesis, 
existsLevelFunctionality, 
functionEquality, 
universeEquality
Latex:
\mforall{}[A,B,C,D:Type].
    \mforall{}P:(A  \mtimes{}  B  \mtimes{}  C  \mtimes{}  D)  {}\mrightarrow{}  \mBbbP{}'.  \{\mexists{}x:A  \mtimes{}  B  \mtimes{}  C  \mtimes{}  D.  P[x]  \mLeftarrow{}{}\mRightarrow{}  \mexists{}a:A.  \mexists{}b:B.  \mexists{}c:C.  \mexists{}d:D.  P[<a,  b,  c,  d>]\}
Date html generated:
2016_05_15-PM-03_23_02
Last ObjectModification:
2015_12_27-PM-01_05_41
Theory : general
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