Nuprl Lemma : setmem-setimages
∀A,B,x:coSet{i:l}.
  ((x ∈ setimages(A;B))
  ⇐⇒ ∃f:coSet{i:l}
       (function-graph{i:l}(A;_.B;f) ∧ (∀z:coSet{i:l}. ((z ∈ x) ⇐⇒ ∃pr:coSet{i:l}. ((pr ∈ f) ∧ seteq(z;snd(pr)))))))
Proof
Definitions occuring in Statement : 
setimages: setimages(A;B), 
function-graph: function-graph{i:l}(A;a.B[a];grph), 
orderedpair-snd: snd(pr), 
setmem: (x ∈ s), 
seteq: seteq(s1;s2), 
coSet: coSet{i:l}, 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
iff: P ⇐⇒ Q, 
and: P ∧ Q
Definitions unfolded in proof : 
function-graph: function-graph{i:l}(A;a.B[a];grph), 
guard: {T}, 
set-function: set-function{i:l}(s; x.f[x]), 
so_apply: x[s], 
so_lambda: λ2x.t[x], 
rev_implies: P ⇐ Q, 
uall: ∀[x:A]. B[x], 
prop: ℙ, 
cand: A c∧ B, 
member: t ∈ T, 
exists: ∃x:A. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q, 
iff: P ⇐⇒ Q, 
setimages: setimages(A;B), 
all: ∀x:A. B[x]
Lemmas referenced : 
snd-orderedpairset, 
orderedpair-snd_functionality, 
orderedpairset_wf, 
setmem-sigmaset, 
sigmaset_wf, 
setsubset-iff, 
setmem_functionality_1, 
setmem_functionality, 
setmem-imageset, 
setunionfun_wf, 
co-seteq-iff, 
seteq_weakening, 
imageset_functionality, 
singleset_functionality, 
seteq_functionality, 
setmem-setunionfun, 
singleset_wf, 
funset_wf, 
setmem-singleset, 
setmem-funset, 
imageset_wf, 
iff_wf, 
all_wf, 
function-graph_wf, 
orderedpair-snd_wf, 
seteq_wf, 
coSet_wf, 
exists_wf, 
setmem_wf
Rules used in proof : 
rename, 
setElimination, 
existsLevelFunctionality, 
andLevelFunctionality, 
independent_functionElimination, 
dependent_functionElimination, 
existsFunctionality, 
impliesFunctionality, 
addLevel, 
setEquality, 
because_Cache, 
cumulativity, 
productEquality, 
lambdaEquality, 
sqequalRule, 
instantiate, 
isectElimination, 
extract_by_obid, 
introduction, 
hypothesis, 
hypothesisEquality, 
dependent_pairFormation, 
thin, 
productElimination, 
sqequalHypSubstitution, 
independent_pairFormation, 
cut, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}A,B,x:coSet\{i:l\}.
    ((x  \mmember{}  setimages(A;B))
    \mLeftarrow{}{}\mRightarrow{}  \mexists{}f:coSet\{i:l\}
              (function-graph\{i:l\}(A;$_{}$.B;f)
              \mwedge{}  (\mforall{}z:coSet\{i:l\}.  ((z  \mmember{}  x)  \mLeftarrow{}{}\mRightarrow{}  \mexists{}pr:coSet\{i:l\}.  ((pr  \mmember{}  f)  \mwedge{}  seteq(z;snd(pr)))))))
Date html generated:
2018_07_29-AM-10_05_55
Last ObjectModification:
2018_07_18-PM-04_43_06
Theory : constructive!set!theory
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