Nuprl Lemma : exists-simp-test
∀T:Type. ∀P:T ⟶ ℙ'. ∀a:T.  (∃x:T. (P[x] ∧ (x = a ∈ T)) 
⇐⇒ P[a])
Proof
Definitions occuring in Statement : 
prop: ℙ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
exists: ∃x:A. B[x]
, 
prop: ℙ
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
subtype_rel: A ⊆r B
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
and_wf, 
equal_wf, 
exists_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
independent_pairFormation, 
sqequalHypSubstitution, 
productElimination, 
thin, 
cut, 
hypothesis, 
addLevel, 
hyp_replacement, 
equalitySymmetry, 
sqequalRule, 
dependent_set_memberEquality, 
hypothesisEquality, 
introduction, 
extract_by_obid, 
isectElimination, 
applyLambdaEquality, 
setElimination, 
rename, 
applyEquality, 
levelHypothesis, 
instantiate, 
cumulativity, 
lambdaEquality, 
productEquality, 
functionExtensionality, 
universeEquality, 
dependent_pairFormation, 
because_Cache, 
functionEquality
Latex:
\mforall{}T:Type.  \mforall{}P:T  {}\mrightarrow{}  \mBbbP{}'.  \mforall{}a:T.    (\mexists{}x:T.  (P[x]  \mwedge{}  (x  =  a))  \mLeftarrow{}{}\mRightarrow{}  P[a])
Date html generated:
2017_10_01-AM-09_10_43
Last ObjectModification:
2017_07_26-PM-04_47_02
Theory : general
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