Nuprl Lemma : Coquand-fan-theorem
∀[T:Type]
  (finite-type(T)
  
⇒ (∀p:wfd-tree(T). ∀A:n:ℕ ⟶ (ℕn ⟶ T) ⟶ ℙ.
        ((∀n:ℕ. ∀s:ℕn ⟶ T.  ((A n s) 
⇒ (∀m:{n...}. ∀t:ℕm ⟶ T.  ((t = s ∈ (ℕn ⟶ T)) 
⇒ (A m t)))))
        
⇒ (p|A)
        
⇒ (∃N:ℕ. ∀m:{N...}. ∀as:ℕm ⟶ T.  (A m as)))))
Proof
Definitions occuring in Statement : 
tree-bars: (p|A)
, 
finite-type: finite-type(T)
, 
wfd-tree: wfd-tree(T)
, 
int_upper: {i...}
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
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
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
wfd-tree: wfd-tree(T)
, 
member: t ∈ T
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
subtype_rel: A ⊆r B
, 
nat: ℕ
, 
prop: ℙ
, 
int_upper: {i...}
, 
uimplies: b supposing a
, 
and: P ∧ Q
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
false: False
, 
not: ¬A
, 
guard: {T}
, 
ge: i ≥ j 
, 
all: ∀x:A. B[x]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
top: Top
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
ifthenelse: if b then t else f fi 
, 
uiff: uiff(P;Q)
, 
bfalse: ff
, 
tree-bars: (p|A)
, 
Wsup: Wsup(a;b)
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
sq_type: SQType(T)
, 
bnot: ¬bb
, 
assert: ↑b
, 
predicate-shift: A_x
, 
seq-append: seq-append(n;m;s1;s2)
, 
less_than: a < b
, 
true: True
, 
squash: ↓T
, 
finite-type: finite-type(T)
, 
pi1: fst(t)
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
l_exists: (∃x∈L. P[x])
, 
nat_plus: ℕ+
, 
select: L[n]
, 
cons: [a / b]
, 
surject: Surj(A;B;f)
, 
seq-single: seq-single(t)
, 
subtract: n - m
, 
nequal: a ≠ b ∈ T 
, 
cand: A c∧ B
Lemmas referenced : 
W-induction, 
bool_wf, 
ifthenelse_wf, 
all_wf, 
nat_wf, 
int_seg_wf, 
int_upper_wf, 
equal_wf, 
subtype_rel_dep_function, 
int_seg_subtype, 
false_wf, 
int_upper_properties, 
nat_properties, 
decidable__le, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
int_upper_subtype_nat, 
tree-bars_wf, 
exists_wf, 
W_wf, 
eqtt_to_assert, 
le_wf, 
int_seg_properties, 
intformless_wf, 
itermConstant_wf, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
predicate-shift_wf, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
finite-type_wf, 
decidable__equal_int, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
itermAdd_wf, 
int_term_value_add_lemma, 
seq-append_wf, 
seq-single_wf, 
lt_int_wf, 
assert_of_lt_int, 
top_wf, 
less_than_wf, 
lelt_wf, 
subtract_wf, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
decidable__lt, 
imax-list-ub, 
cons_wf, 
map_wf, 
upto_wf, 
length_of_cons_lemma, 
non_neg_length, 
map_length, 
length_wf, 
add_nat_plus, 
length_wf_nat, 
nat_plus_wf, 
nat_plus_properties, 
add-is-int-iff, 
select_wf, 
add-associates, 
add-swap, 
add-commutes, 
zero-add, 
not-le-2, 
condition-implies-le, 
minus-add, 
minus-one-mul, 
minus-one-mul-top, 
add_functionality_wrt_le, 
le-add-cancel, 
eq_int_wf, 
assert_of_eq_int, 
int_subtype_base, 
neg_assert_of_eq_int, 
add-member-int_seg2, 
l_exists_iff, 
l_member_wf, 
cons_member, 
member_map, 
equal-wf-T-base, 
member_upto2, 
int_seg_subtype_nat
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
thin, 
instantiate, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
cumulativity, 
hypothesis, 
sqequalRule, 
lambdaEquality, 
hypothesisEquality, 
universeEquality, 
voidEquality, 
functionEquality, 
applyEquality, 
natural_numberEquality, 
setElimination, 
rename, 
because_Cache, 
functionExtensionality, 
independent_isectElimination, 
independent_pairFormation, 
dependent_functionElimination, 
unionElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
computeAll, 
equalityElimination, 
productElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
dependent_set_memberEquality, 
applyLambdaEquality, 
promote_hyp, 
addLevel, 
hyp_replacement, 
levelHypothesis, 
addEquality, 
lessCases, 
sqequalAxiom, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
pointwiseFunctionality, 
baseApply, 
closedConclusion, 
minusEquality, 
int_eqReduceTrueSq, 
int_eqReduceFalseSq, 
setEquality, 
productEquality, 
inrFormation
Latex:
\mforall{}[T:Type]
    (finite-type(T)
    {}\mRightarrow{}  (\mforall{}p:wfd-tree(T).  \mforall{}A:n:\mBbbN{}  {}\mrightarrow{}  (\mBbbN{}n  {}\mrightarrow{}  T)  {}\mrightarrow{}  \mBbbP{}.
                ((\mforall{}n:\mBbbN{}.  \mforall{}s:\mBbbN{}n  {}\mrightarrow{}  T.    ((A  n  s)  {}\mRightarrow{}  (\mforall{}m:\{n...\}.  \mforall{}t:\mBbbN{}m  {}\mrightarrow{}  T.    ((t  =  s)  {}\mRightarrow{}  (A  m  t)))))
                {}\mRightarrow{}  (p|A)
                {}\mRightarrow{}  (\mexists{}N:\mBbbN{}.  \mforall{}m:\{N...\}.  \mforall{}as:\mBbbN{}m  {}\mrightarrow{}  T.    (A  m  as)))))
Date html generated:
2017_04_17-AM-09_39_01
Last ObjectModification:
2017_02_27-PM-05_36_19
Theory : fan-theorem
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