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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