Nuprl Lemma : fan-theorem
∀[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 : 
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
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
prop: ℙ
, 
all: ∀x:A. B[x]
, 
sq_exists: ∃x:{A| B[x]}
, 
exists: ∃x:A. B[x]
, 
so_lambda: λ2x.t[x]
, 
nat: ℕ
, 
int_seg: {i..j-}
, 
subtype_rel: A ⊆r B
, 
so_apply: x[s]
, 
uimplies: b supposing a
, 
le: A ≤ B
, 
and: P ∧ Q
, 
less_than': less_than'(a;b)
, 
false: False
, 
not: ¬A
, 
uiff: uiff(P;Q)
, 
dec-predicate: Decidable(X)
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
outl: outl(x)
Lemmas referenced : 
dec-predicate_wf, 
list_wf, 
bool_wf, 
tbar_wf, 
simple-fan-theorem, 
nat_wf, 
all_wf, 
exists_wf, 
int_seg_wf, 
map_wf, 
subtype_rel_dep_function, 
int_seg_subtype_nat, 
false_wf, 
subtype_rel_self, 
upto_wf, 
not_over_exists, 
not_wf, 
int_seg_decide_wf, 
decidable_wf, 
equal_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
rename, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesis, 
hypothesisEquality, 
functionEquality, 
cumulativity, 
universeEquality, 
dependent_functionElimination, 
setElimination, 
dependent_pairFormation, 
sqequalRule, 
lambdaEquality, 
natural_numberEquality, 
applyEquality, 
because_Cache, 
independent_isectElimination, 
independent_pairFormation, 
addLevel, 
impliesFunctionality, 
productElimination, 
independent_functionElimination, 
voidElimination, 
introduction, 
instantiate, 
equalityTransitivity, 
equalitySymmetry, 
unionElimination
Latex:
\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:
2016_05_15-PM-10_05_18
Last ObjectModification:
2015_12_27-PM-05_51_09
Theory : bar!induction
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