Nuprl Lemma : singleitem-singleset
∀a:coSet{i:l}. seteq(singleitem({a});a)
Proof
Definitions occuring in Statement : 
singleitem: singleitem(s), 
singleset: {a}, 
seteq: seteq(s1;s2), 
coSet: coSet{i:l}, 
all: ∀x:A. B[x]
Definitions unfolded in proof : 
guard: {T}, 
exists: ∃x:A. B[x], 
so_apply: x[s], 
so_lambda: λ2x.t[x], 
prop: ℙ, 
singleitem: singleitem(s), 
implies: P ⇒ Q, 
rev_implies: P ⇐ Q, 
and: P ∧ Q, 
iff: P ⇐⇒ Q, 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
all: ∀x:A. B[x]
Lemmas referenced : 
setmem_functionality, 
unionset_wf, 
setmem-unionset, 
iff_wf, 
setmem-singleset, 
seteq_weakening, 
setmem_wf, 
seteq_wf, 
exists_wf, 
coSet_wf, 
singleset_wf, 
singleitem_wf, 
co-seteq-iff
Rules used in proof : 
existsLevelFunctionality, 
andLevelFunctionality, 
existsFunctionality, 
impliesFunctionality, 
addLevel, 
because_Cache, 
dependent_pairFormation, 
cumulativity, 
productEquality, 
lambdaEquality, 
sqequalRule, 
instantiate, 
independent_pairFormation, 
independent_functionElimination, 
productElimination, 
hypothesis, 
hypothesisEquality, 
isectElimination, 
thin, 
dependent_functionElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}a:coSet\{i:l\}.  seteq(singleitem(\{a\});a)
Date html generated:
2018_07_29-AM-09_59_24
Last ObjectModification:
2018_07_18-PM-03_03_29
Theory : constructive!set!theory
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