Nuprl Lemma : setmem-singleset
∀a,x:coSet{i:l}.  ((x ∈ {a}) 
⇐⇒ seteq(x;a))
Proof
Definitions occuring in Statement : 
singleset: {a}
, 
setmem: (x ∈ s)
, 
seteq: seteq(s1;s2)
, 
coSet: coSet{i:l}
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
Definitions unfolded in proof : 
rev_implies: P 
⇐ Q
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
prop: ℙ
, 
exists: ∃x:A. B[x]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
iff: P 
⇐⇒ Q
, 
top: Top
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
mk-coset: mk-coset(T;f)
, 
singleset: {a}
, 
all: ∀x:A. B[x]
Lemmas referenced : 
coSet_wf, 
it_wf, 
seteq_wf, 
unit_wf2, 
exists_wf, 
setmem-mk-coset
Rules used in proof : 
because_Cache, 
dependent_pairFormation, 
hypothesisEquality, 
lambdaEquality, 
productElimination, 
independent_pairFormation, 
hypothesis, 
voidEquality, 
voidElimination, 
isect_memberEquality, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
sqequalRule, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}a,x:coSet\{i:l\}.    ((x  \mmember{}  \{a\})  \mLeftarrow{}{}\mRightarrow{}  seteq(x;a))
Date html generated:
2018_07_29-AM-09_53_17
Last ObjectModification:
2018_07_18-AM-10_55_36
Theory : constructive!set!theory
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