Nuprl Lemma : all-union
∀[A,B:Type].  ∀P:(A + B) ⟶ ℙ. (∀x:A + B. P[x] 
⇐⇒ (∀a:A. P[inl a]) ∧ (∀b:B. P[inr b ]))
Proof
Definitions occuring in Statement : 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
function: x:A ⟶ B[x]
, 
inr: inr x 
, 
inl: inl x
, 
union: left + right
, 
universe: Type
Definitions unfolded in proof : 
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
, 
guard: {T}
Lemmas referenced : 
all_wf, 
and_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
independent_pairFormation, 
hypothesisEquality, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
unionEquality, 
sqequalRule, 
lambdaEquality, 
applyEquality, 
hypothesis, 
productElimination, 
unionElimination, 
inlEquality, 
inrEquality, 
functionEquality, 
cumulativity, 
universeEquality, 
dependent_functionElimination
Latex:
\mforall{}[A,B:Type].    \mforall{}P:(A  +  B)  {}\mrightarrow{}  \mBbbP{}.  (\mforall{}x:A  +  B.  P[x]  \mLeftarrow{}{}\mRightarrow{}  (\mforall{}a:A.  P[inl  a])  \mwedge{}  (\mforall{}b:B.  P[inr  b  ]))
Date html generated:
2016_05_15-PM-03_24_39
Last ObjectModification:
2015_12_27-PM-01_06_08
Theory : general
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