Nuprl Lemma : bag-member-single-weak
∀[T:Type]. ∀[x,y:T].  (x ↓∈ {y} ⇐⇒ x = y ∈ T)
Proof
Definitions occuring in Statement : 
bag-member: x ↓∈ bs, 
single-bag: {x}, 
uall: ∀[x:A]. B[x], 
iff: P ⇐⇒ Q, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
implies: P ⇒ Q, 
uiff: uiff(P;Q), 
uimplies: b supposing a, 
prop: ℙ, 
all: ∀x:A. B[x], 
rev_implies: P ⇐ Q, 
bag-member: x ↓∈ bs, 
squash: ↓T
Lemmas referenced : 
bag-member-single, 
bag-member_wf, 
single-bag_wf, 
equal_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
independent_pairFormation, 
lambdaFormation, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
because_Cache, 
hypothesisEquality, 
hypothesis, 
productElimination, 
independent_isectElimination, 
cumulativity, 
dependent_functionElimination, 
sqequalRule, 
independent_pairEquality, 
lambdaEquality, 
axiomEquality, 
imageElimination, 
imageMemberEquality, 
baseClosed, 
isect_memberEquality, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[x,y:T].    (x  \mdownarrow{}\mmember{}  \{y\}  \mLeftarrow{}{}\mRightarrow{}  x  =  y)
Date html generated:
2017_10_01-AM-08_53_35
Last ObjectModification:
2017_07_26-PM-04_35_19
Theory : bags
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