Nuprl Lemma : co-regext-Regularcoset
The proof that ⌜co-regext(a)⌝ is regular goes through as before, just
using co- versions of everything.⋅
∀a:coSet{i:l}. cRegular(co-regext(a))
Proof
Definitions occuring in Statement : 
co-regext: co-regext(a)
, 
Regularcoset: cRegular(A)
, 
coSet: coSet{i:l}
, 
all: ∀x:A. B[x]
Definitions unfolded in proof : 
Wsup: Wsup(a;b)
, 
mk-set: f"(T)
, 
ext-eq: A ≡ B
, 
regextfun: regextfun(f;w)
, 
guard: {T}
, 
exists: ∃x:A. B[x]
, 
top: Top
, 
co-regext: co-regext(a)
, 
uimplies: b supposing a
, 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
mk-coset: mk-coset(T;f)
, 
subtype_rel: A ⊆r B
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
and: P ∧ Q
, 
Regularcoset: cRegular(A)
, 
all: ∀x:A. B[x]
Lemmas referenced : 
exists_wf, 
mk-coset_wf, 
seteq_wf, 
regextfun_wf, 
coW_wf, 
subtype_rel_weakening, 
set-dom_wf, 
coW-ext, 
setmem-mk-coset, 
coset-relation_wf, 
set_wf, 
subtype_rel_self, 
setmem_wf, 
coSet_wf, 
subtype_rel_dep_function, 
co-regext_wf, 
mv-map_wf, 
co-regext-lemma, 
coSet_subtype, 
subtype_coSet, 
co-regext-transitive
Rules used in proof : 
dependent_pairFormation, 
productEquality, 
voidEquality, 
voidElimination, 
isect_memberEquality, 
rename, 
setElimination, 
independent_isectElimination, 
setEquality, 
universeEquality, 
cumulativity, 
functionEquality, 
lambdaEquality, 
because_Cache, 
instantiate, 
isectElimination, 
independent_functionElimination, 
productElimination, 
sqequalRule, 
applyEquality, 
hypothesis_subsumption, 
hypothesis, 
hypothesisEquality, 
thin, 
dependent_functionElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
independent_pairFormation, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}a:coSet\{i:l\}.  cRegular(co-regext(a))
Date html generated:
2018_07_29-AM-10_08_11
Last ObjectModification:
2018_07_21-PM-08_24_03
Theory : constructive!set!theory
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