Nuprl Lemma : fan-realizer_wf
fan-realizer ∈ ∀[X:(𝔹 List) ⟶ ℙ]. (tbar(𝔹;X) ⇒ Decidable(X) ⇒ (∃k:ℕ. ∀f:ℕ ⟶ 𝔹. ∃n:ℕk. (X map(f;upto(n)))))
Proof
Definitions occuring in Statement : 
fan-realizer: fan-realizer, 
tbar: tbar(T;X), 
dec-predicate: Decidable(X), 
upto: upto(n), 
map: map(f;as), 
list: T List, 
int_seg: {i..j-}, 
nat: ℕ, 
bool: 𝔹, 
uall: ∀[x:A]. B[x], 
prop: ℙ, 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
implies: P ⇒ Q, 
member: t ∈ T, 
apply: f a, 
function: x:A ⟶ B[x], 
natural_number: $n
Definitions unfolded in proof : 
member: t ∈ T, 
fan-theorem, 
simple-fan-theorem, 
simple_fan_theorem, 
basic_bar_induction, 
uall: ∀[x:A]. B[x], 
so_lambda: so_lambda4, 
so_apply: x[s1;s2;s3;s4], 
uimplies: b supposing a, 
strict4: strict4(F), 
and: P ∧ Q, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
has-value: (a)↓, 
prop: ℙ, 
or: P ∨ Q, 
squash: ↓T, 
false: False, 
seq-normalize: seq-normalize(n;s), 
fan-realizer: fan-realizer, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
uiff: uiff(P;Q), 
less_than: a < b, 
less_than': less_than'(a;b), 
true: True, 
not: ¬A, 
bfalse: ff, 
exists: ∃x:A. B[x], 
sq_type: SQType(T), 
guard: {T}, 
bnot: ¬bb, 
ifthenelse: if b then t else f fi , 
assert: ↑b, 
rev_implies: P ⇐ Q, 
iff: P ⇐⇒ Q, 
pi1: fst(t), 
nat: ℕ, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
subtype_rel: A ⊆r B, 
int_seg: {i..j-}, 
lelt: i ≤ j < k, 
le: A ≤ B
Lemmas referenced : 
fan-theorem, 
lifting-strict-less, 
value-type-has-value, 
int-value-type, 
has-value_wf_base, 
istype-base, 
istype-universe, 
exception-not-value, 
is-exception_wf, 
strictness-apply, 
lt_int_wf, 
eqtt_to_assert, 
assert_of_lt_int, 
istype-top, 
bottom-sqle, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
assert-bnot, 
iff_weakening_uiff, 
assert_wf, 
less_than_wf, 
istype-less_than, 
bottom_diverge, 
exception-not-bottom, 
dec-predicate_wf, 
list_wf, 
tbar_wf, 
nat_wf, 
set-value-type, 
le_wf, 
istype-int, 
istype-nat, 
int_seg_wf, 
map_wf, 
upto_wf, 
subtype_rel_function, 
int_seg_subtype_nat, 
istype-false, 
subtype_rel_self, 
simple-fan-theorem, 
simple_fan_theorem, 
basic_bar_induction
Rules used in proof : 
cut, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
instantiate, 
extract_by_obid, 
hypothesis, 
sqequalHypSubstitution, 
sqequalRule, 
introduction, 
isectElimination, 
thin, 
baseClosed, 
Error :memTop, 
independent_isectElimination, 
independent_pairFormation, 
lambdaFormation_alt, 
callbyvalueAdd, 
baseApply, 
closedConclusion, 
hypothesisEquality, 
productElimination, 
intEquality, 
because_Cache, 
universeIsType, 
addExceptionCases, 
exceptionSqequal, 
inlFormation_alt, 
imageMemberEquality, 
imageElimination, 
sqleReflexivity, 
independent_functionElimination, 
voidElimination, 
isect_memberEquality_alt, 
lambdaEquality_alt, 
sqequalSqle, 
divergentSqle, 
callbyvalueLess, 
inhabitedIsType, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
lessCases, 
isect_memberFormation_alt, 
axiomSqEquality, 
isectIsTypeImplies, 
natural_numberEquality, 
dependent_pairFormation_alt, 
equalityIstype, 
promote_hyp, 
dependent_functionElimination, 
cumulativity, 
lessExceptionCases, 
axiomSqleEquality, 
callbyvalueCallbyvalue, 
callbyvalueReduce, 
callbyvalueExceptionCases, 
functionIsType, 
universeEquality, 
applyEquality, 
isectIsType, 
productIsType, 
setElimination, 
rename, 
productEquality, 
functionEquality
Latex:
fan-realizer  \mmember{}  \mforall{}[X:(\mBbbB{}  List)  {}\mrightarrow{}  \mBbbP{}]
                                  (tbar(\mBbbB{};X)  {}\mRightarrow{}  Decidable(X)  {}\mRightarrow{}  (\mexists{}k:\mBbbN{}.  \mforall{}f:\mBbbN{}  {}\mrightarrow{}  \mBbbB{}.  \mexists{}n:\mBbbN{}k.  (X  map(f;upto(n)))))
Date html generated:
2020_05_20-AM-09_07_38
Last ObjectModification:
2020_01_10-PM-03_32_46
Theory : bar!induction
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