Nuprl Lemma : fset-to-list
∀[T:Type]
  ∀eq:EqDecider(T)
    ∀[R:T ⟶ T ⟶ ℙ]
      ((∀a,b:T.  Dec(R a b)) 
⇒ Linorder(T;a,b.R a b) 
⇒ (∀s:fset(T). ∃L:T List. ∀x:T. (x ∈ s 
⇐⇒ (x ∈ L))))
Proof
Definitions occuring in Statement : 
fset-member: a ∈ s
, 
fset: fset(T)
, 
l_member: (x ∈ l)
, 
list: T List
, 
deq: EqDecider(T)
, 
linorder: Linorder(T;x,y.R[x; y])
, 
decidable: Dec(P)
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
exists: ∃x:A. B[x]
, 
prop: ℙ
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
and: P ∧ Q
, 
subtype_rel: A ⊆r B
, 
uimplies: b supposing a
, 
pi1: fst(t)
, 
fset: fset(T)
, 
quotient: x,y:A//B[x; y]
, 
squash: ↓T
, 
true: True
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
cand: A c∧ B
, 
linorder: Linorder(T;x,y.R[x; y])
, 
order: Order(T;x,y.R[x; y])
, 
fset-member: a ∈ s
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
sq_type: SQType(T)
, 
guard: {T}
, 
false: False
, 
not: ¬A
, 
l_contains: A ⊆ B
, 
uiff: uiff(P;Q)
, 
set-equal: set-equal(T;x;y)
Lemmas referenced : 
sorted-by-exists2, 
decidable-equal-deq, 
fset_wf, 
linorder_wf, 
all_wf, 
decidable_wf, 
deq_wf, 
list_wf, 
exists_wf, 
sorted-by_wf, 
subtype_rel_dep_function, 
l_member_wf, 
subtype_rel_self, 
set_wf, 
no_repeats_wf, 
l_contains_wf, 
equal_wf, 
set-equal_wf, 
set-equal-reflex, 
equal-wf-base, 
member_wf, 
squash_wf, 
true_wf, 
set-equal-l_contains, 
l_contains_transitivity, 
sorted-by-unique, 
iff_wf, 
fset-member_wf, 
fset-member_witness, 
assert-deq-member, 
decidable__assert, 
deq-member_wf, 
subtype_base_sq, 
int_subtype_base, 
l_all_iff, 
assert_witness, 
assert_equal, 
assert_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
independent_functionElimination, 
because_Cache, 
hypothesis, 
dependent_functionElimination, 
promote_hyp, 
productElimination, 
cumulativity, 
sqequalRule, 
lambdaEquality, 
applyEquality, 
functionExtensionality, 
functionEquality, 
universeEquality, 
productEquality, 
instantiate, 
setEquality, 
independent_isectElimination, 
setElimination, 
rename, 
dependent_pairFormation, 
equalityTransitivity, 
equalitySymmetry, 
pointwiseFunctionality, 
pertypeElimination, 
imageElimination, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
independent_pairFormation, 
unionElimination, 
intEquality, 
voidElimination, 
addLevel, 
impliesFunctionality
Latex:
\mforall{}[T:Type]
    \mforall{}eq:EqDecider(T)
        \mforall{}[R:T  {}\mrightarrow{}  T  {}\mrightarrow{}  \mBbbP{}]
            ((\mforall{}a,b:T.    Dec(R  a  b))
            {}\mRightarrow{}  Linorder(T;a,b.R  a  b)
            {}\mRightarrow{}  (\mforall{}s:fset(T).  \mexists{}L:T  List.  \mforall{}x:T.  (x  \mmember{}  s  \mLeftarrow{}{}\mRightarrow{}  (x  \mmember{}  L))))
Date html generated:
2017_04_17-AM-09_23_08
Last ObjectModification:
2017_02_27-PM-05_26_33
Theory : finite!sets
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