Nuprl Lemma : least-closed-set-inductively-defined
∀[R:Set{i:l} ⟶ Set{i:l} ⟶ ℙ']
  ∀B:Set{i:l}. ∀G:Set{i:l} ⟶ Set{i:l}.
    ((∀x,a:Set{i:l}.  (R[x;a] 
⇒ (∃b:Set{i:l}. ((b ∈ B) ∧ setimage{i:l}(x;b)))))
    
⇒ (∀x,z:Set{i:l}.  ((z ∈ G x) 
⇐⇒ ∃A:Set{i:l}. ((A ⊆ x) ∧ R[A;z])))
    
⇒ inductively-defined{i:l}(x,a.R[x;a];least-closed-set(B;G)))
Proof
Definitions occuring in Statement : 
least-closed-set: least-closed-set(B;G)
, 
inductively-defined: inductively-defined{i:l}(x,a.R[x; a];s)
, 
setimage: setimage{i:l}(x;b)
, 
setsubset: (a ⊆ b)
, 
Set: Set{i:l}
, 
setmem: (x ∈ s)
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s1;s2]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
apply: f a
, 
function: x:A ⟶ B[x]
Definitions unfolded in proof : 
so_lambda: λ2x y.t[x; y]
, 
mv-map:  R:(A 
⇒ B)
, 
pi1: fst(t)
, 
set-relation: SetRelation(R)
, 
Regularset: Regular(A)
, 
itersetfun: itersetfun(s.G[s];a)
, 
uimplies: b supposing a
, 
set-function: set-function{i:l}(s; x.f[x])
, 
setimage: setimage{i:l}(x;b)
, 
guard: {T}
, 
relclosed-set: closed(x,a.R[x; a])s
, 
inductively-defined: inductively-defined{i:l}(x,a.R[x; a];s)
, 
least-closed-set: least-closed-set(B;G)
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s1;s2]
, 
cand: A c∧ B
, 
prop: ℙ
, 
exists: ∃x:A. B[x]
, 
rev_implies: P 
⇐ Q
, 
and: P ∧ Q
, 
iff: P 
⇐⇒ Q
, 
subtype_rel: A ⊆r B
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
itersetfun-subset-fixpoint, 
relclosed-set_wf, 
setmem_functionality, 
seteq_inversion, 
setmem_functionality_1, 
setunionfun_wf2, 
itersetfun_functionality, 
coSet-mem-Set-implies-Set, 
seteq_functionality, 
setmem-setunionfun, 
seteq_wf, 
seteq_weakening, 
setsubset-iff, 
coSet_wf, 
coSet-subtype-Set, 
itersetfun_wf, 
setunionfun_wf, 
equal_wf, 
Regularset_wf, 
regext_wf2, 
setTC-transitive, 
subset-regext, 
setTC-contains, 
regext_wf, 
regext-Regularset, 
setimage_wf, 
subtype_rel_self, 
iff_wf, 
all_wf, 
setmem_wf, 
Set_wf, 
exists_wf, 
setsubset_wf, 
set-subtype-coSet, 
setsubset_transitivity, 
setsubset-iff2
Rules used in proof : 
setElimination, 
independent_isectElimination, 
functionExtensionality, 
dependent_pairEquality, 
rename, 
setEquality, 
equalitySymmetry, 
equalityTransitivity, 
universeEquality, 
functionEquality, 
impliesFunctionality, 
allFunctionality, 
addLevel, 
lambdaEquality, 
instantiate, 
isectElimination, 
cumulativity, 
productEquality, 
promote_hyp, 
independent_pairFormation, 
dependent_pairFormation, 
independent_functionElimination, 
productElimination, 
sqequalRule, 
because_Cache, 
hypothesis, 
hypothesisEquality, 
applyEquality, 
thin, 
dependent_functionElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
lambdaFormation, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}[R:Set\{i:l\}  {}\mrightarrow{}  Set\{i:l\}  {}\mrightarrow{}  \mBbbP{}']
    \mforall{}B:Set\{i:l\}.  \mforall{}G:Set\{i:l\}  {}\mrightarrow{}  Set\{i:l\}.
        ((\mforall{}x,a:Set\{i:l\}.    (R[x;a]  {}\mRightarrow{}  (\mexists{}b:Set\{i:l\}.  ((b  \mmember{}  B)  \mwedge{}  setimage\{i:l\}(x;b)))))
        {}\mRightarrow{}  (\mforall{}x,z:Set\{i:l\}.    ((z  \mmember{}  G  x)  \mLeftarrow{}{}\mRightarrow{}  \mexists{}A:Set\{i:l\}.  ((A  \msubseteq{}  x)  \mwedge{}  R[A;z])))
        {}\mRightarrow{}  inductively-defined\{i:l\}(x,a.R[x;a];least-closed-set(B;G)))
Date html generated:
2018_07_29-AM-10_09_54
Last ObjectModification:
2018_07_20-PM-01_27_24
Theory : constructive!set!theory
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