Nuprl Lemma : simple_fan_theorem
∀[X:n:ℕ ⟶ (ℕn ⟶ 𝔹) ⟶ ℙ]
  (∀n:ℕ. ∀s:ℕn ⟶ 𝔹.  Dec(X[n;s])) 
⇒ (∃k:ℕ [(∀f:ℕ ⟶ 𝔹. ∃n:ℕk. X[n;f])]) supposing ∀f:ℕ ⟶ 𝔹. (↓∃n:ℕ. X[n;f])
Proof
Definitions occuring in Statement : 
int_seg: {i..j-}
, 
nat: ℕ
, 
bool: 𝔹
, 
decidable: Dec(P)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s1;s2]
, 
all: ∀x:A. B[x]
, 
sq_exists: ∃x:A [B[x]]
, 
exists: ∃x:A. B[x]
, 
squash: ↓T
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
uimplies: b supposing a
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
squash: ↓T
, 
implies: P 
⇒ Q
, 
so_lambda: λ2x y.t[x; y]
, 
so_lambda: λ2x.t[x]
, 
nat: ℕ
, 
so_apply: x[s1;s2]
, 
int_seg: {i..j-}
, 
guard: {T}
, 
sq_stable: SqStable(P)
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
false: False
, 
not: ¬A
, 
so_apply: x[s]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
uiff: uiff(P;Q)
, 
subtract: n - m
, 
top: Top
, 
true: True
, 
sq_exists: ∃x:A [B[x]]
, 
exists: ∃x:A. B[x]
, 
less_than: a < b
, 
seq-append: seq-append(n;m;s1;s2)
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
bfalse: ff
, 
sq_type: SQType(T)
, 
bnot: ¬bb
, 
ifthenelse: if b then t else f fi 
, 
assert: ↑b
, 
ge: i ≥ j 
, 
nat_plus: ℕ+
, 
seq-adjoin: s++t
Lemmas referenced : 
nat_wf, 
bool_wf, 
basic_bar_induction, 
sq_exists_wf, 
all_wf, 
exists_wf, 
int_seg_wf, 
add_nat_wf, 
sq_stable__le, 
equal_wf, 
le_wf, 
seq-append_wf, 
int_seg_subtype_nat, 
false_wf, 
subtype_rel_function, 
subtype_rel_self, 
decidable__le, 
not-le-2, 
condition-implies-le, 
minus-add, 
minus-one-mul, 
zero-add, 
minus-one-mul-top, 
add-associates, 
add-swap, 
add-commutes, 
add_functionality_wrt_le, 
add-zero, 
le-add-cancel, 
seq-adjoin_wf, 
decidable_wf, 
squash_wf, 
and_wf, 
less_than_wf, 
lt_int_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
top_wf, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
not-lt-2, 
less-iff-le, 
btrue_wf, 
set_wf, 
set-value-type, 
int-value-type, 
bfalse_wf, 
add-member-int_seg2, 
subtract_wf, 
le-add-cancel2, 
decidable__lt, 
minus-minus, 
sq_stable__and, 
sq_stable__less_than, 
member-less_than, 
le_reflexive, 
one-mul, 
add-mul-special, 
two-mul, 
mul-distributes-right, 
zero-mul, 
minus-zero, 
omega-shadow, 
mul-distributes, 
mul-commutes, 
mul-associates, 
mul-swap, 
nat_properties, 
int_subtype_base, 
iff_imp_equal_bool, 
assert_wf, 
true_wf, 
not-less-implies-equal, 
le-add-cancel-alt, 
set_subtype_base, 
decidable__int_equal, 
not-equal-2, 
less_than_transitivity1, 
less_than_irreflexivity
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
cut, 
introduction, 
sqequalRule, 
sqequalHypSubstitution, 
lambdaEquality, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
imageElimination, 
hypothesis, 
imageMemberEquality, 
baseClosed, 
functionEquality, 
extract_by_obid, 
rename, 
lambdaFormation, 
isectElimination, 
because_Cache, 
natural_numberEquality, 
setElimination, 
applyEquality, 
functionExtensionality, 
dependent_set_memberEquality, 
addEquality, 
independent_functionElimination, 
productElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_isectElimination, 
independent_pairFormation, 
unionElimination, 
voidElimination, 
isect_memberEquality, 
voidEquality, 
intEquality, 
minusEquality, 
cumulativity, 
universeEquality, 
dependent_set_memberFormation, 
dependent_pairFormation, 
addLevel, 
hyp_replacement, 
levelHypothesis, 
equalityElimination, 
lessCases, 
axiomSqEquality, 
promote_hyp, 
instantiate, 
cutEval, 
multiplyEquality
Latex:
\mforall{}[X:n:\mBbbN{}  {}\mrightarrow{}  (\mBbbN{}n  {}\mrightarrow{}  \mBbbB{})  {}\mrightarrow{}  \mBbbP{}]
    (\mforall{}n:\mBbbN{}.  \mforall{}s:\mBbbN{}n  {}\mrightarrow{}  \mBbbB{}.    Dec(X[n;s]))  {}\mRightarrow{}  (\mexists{}k:\mBbbN{}  [(\mforall{}f:\mBbbN{}  {}\mrightarrow{}  \mBbbB{}.  \mexists{}n:\mBbbN{}k.  X[n;f])]) 
    supposing  \mforall{}f:\mBbbN{}  {}\mrightarrow{}  \mBbbB{}.  (\mdownarrow{}\mexists{}n:\mBbbN{}.  X[n;f])
Date html generated:
2019_06_20-AM-11_32_31
Last ObjectModification:
2018_08_20-PM-09_32_25
Theory : bool_1
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