Nuprl Lemma : regext-Regularset
∀a:Set{i:l}. Regular(regext(a))
Proof
Definitions occuring in Statement : 
regext: regext(a)
, 
Regularset: Regular(A)
, 
Set: Set{i:l}
, 
all: ∀x:A. B[x]
Definitions unfolded in proof : 
set-relation: SetRelation(R)
, 
rev_implies: P 
⇐ Q
, 
iff: P 
⇐⇒ Q
, 
guard: {T}
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
onto-map: R:(A ─>> B)
, 
mv-map:  R:(A 
⇒ B)
, 
cand: A c∧ B
, 
coset-relation: coSetRelation(R)
, 
exists: ∃x:A. B[x]
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
implies: P 
⇒ Q
, 
Regularset: Regular(A)
, 
and: P ∧ Q
, 
Regularcoset: cRegular(A)
, 
subtype_rel: A ⊆r B
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
Lemmas referenced : 
seteq_inversion, 
setmem_functionality_1, 
set-relation_wf, 
onto-map_wf, 
set_wf, 
subtype_rel_self, 
coSet-subtype-Set, 
subtype_rel_dep_function, 
mv-map_wf, 
seteq_wf, 
coSet_wf, 
regext_wf2, 
coSet-mem-Set-implies-Set, 
Set_wf, 
regext_wf, 
setmem_wf, 
set-subtype-coSet, 
regext-Regularcoset
Rules used in proof : 
setEquality, 
functionEquality, 
instantiate, 
dependent_pairFormation, 
independent_isectElimination, 
functionExtensionality, 
universeEquality, 
cumulativity, 
because_Cache, 
isectElimination, 
productEquality, 
lambdaEquality, 
independent_functionElimination, 
independent_pairFormation, 
productElimination, 
sqequalRule, 
applyEquality, 
hypothesisEquality, 
thin, 
dependent_functionElimination, 
sqequalHypSubstitution, 
hypothesis, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
extract_by_obid, 
introduction, 
cut
Latex:
\mforall{}a:Set\{i:l\}.  Regular(regext(a))
Date html generated:
2018_07_29-AM-10_07_41
Last ObjectModification:
2018_07_20-PM-01_48_22
Theory : constructive!set!theory
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