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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