Nuprl Lemma : l_find_wf
∀[T:Type]. ∀[L:T List]. ∀[P:{x:T| (x ∈ L)}  ⟶ 𝔹].
  (l_find(L;P) ∈ (∃x:T [(∃i:ℕ||L||. ((x = L[i] ∈ T) ∧ (↑(P x)) ∧ (∀j:ℕi. (¬↑(P L[j])))))]) ∨ (↓∀i:ℕ||L||. (¬↑(P L[i]))))
Proof
Definitions occuring in Statement : 
l_find: l_find(L;P)
, 
l_member: (x ∈ l)
, 
select: L[n]
, 
length: ||as||
, 
list: T List
, 
int_seg: {i..j-}
, 
assert: ↑b
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
sq_exists: ∃x:A [B[x]]
, 
exists: ∃x:A. B[x]
, 
not: ¬A
, 
squash: ↓T
, 
or: P ∨ Q
, 
and: P ∧ Q
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
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]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
nat: ℕ
, 
implies: P 
⇒ Q
, 
false: False
, 
ge: i ≥ j 
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
not: ¬A
, 
top: Top
, 
and: P ∧ Q
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
or: P ∨ Q
, 
select: L[n]
, 
nil: []
, 
it: ⋅
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
l_find: l_find(L;P)
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
squash: ↓T
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
sq_exists: ∃x:A [B[x]]
, 
cons: [a / b]
, 
colength: colength(L)
, 
decidable: Dec(P)
, 
sq_type: SQType(T)
, 
less_than: a < b
, 
less_than': less_than'(a;b)
, 
exposed-bfalse: exposed-bfalse
, 
bool: 𝔹
, 
unit: Unit
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
bnot: ¬bb
, 
assert: ↑b
, 
le: A ≤ B
, 
nat_plus: ℕ+
, 
true: True
, 
cand: A c∧ B
, 
l_member: (x ∈ l)
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
subtract: n - m
Lemmas referenced : 
nat_properties, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
ge_wf, 
less_than_wf, 
l_member_wf, 
bool_wf, 
equal-wf-T-base, 
nat_wf, 
colength_wf_list, 
less_than_transitivity1, 
less_than_irreflexivity, 
list-cases, 
length_of_nil_lemma, 
stuck-spread, 
base_wf, 
reduce_nil_lemma, 
int_seg_properties, 
assert_wf, 
nil_wf, 
int_seg_wf, 
sq_exists_wf, 
exists_wf, 
all_wf, 
not_wf, 
product_subtype_list, 
spread_cons_lemma, 
intformeq_wf, 
itermAdd_wf, 
int_formula_prop_eq_lemma, 
int_term_value_add_lemma, 
decidable__le, 
intformnot_wf, 
int_formula_prop_not_lemma, 
le_wf, 
equal_wf, 
subtract_wf, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
subtype_base_sq, 
set_subtype_base, 
int_subtype_base, 
decidable__equal_int, 
length_of_cons_lemma, 
reduce_cons_lemma, 
eqtt_to_assert, 
eqff_to_assert, 
bool_cases_sqequal, 
bool_subtype_base, 
assert-bnot, 
cons_wf, 
list_wf, 
false_wf, 
add_nat_plus, 
length_wf_nat, 
nat_plus_wf, 
nat_plus_properties, 
decidable__lt, 
add-is-int-iff, 
lelt_wf, 
length_wf, 
select-cons-hd, 
select_wf, 
int_seg_subtype_nat, 
non_neg_length, 
list-subtype, 
squash_wf, 
subtype_rel_dep_function, 
subtype_rel_sets, 
cons_member, 
subtype_rel_self, 
set_wf, 
add-member-int_seg2, 
select-cons-tl, 
add-subtract-cancel, 
select-cons, 
le_int_wf, 
assert_of_le_int, 
or_wf, 
subtype_rel_list_set
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
thin, 
lambdaFormation, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
sqequalRule, 
intWeakElimination, 
natural_numberEquality, 
independent_isectElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
independent_functionElimination, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
functionEquality, 
setEquality, 
cumulativity, 
applyEquality, 
because_Cache, 
unionElimination, 
baseClosed, 
inrEquality, 
productElimination, 
functionExtensionality, 
imageMemberEquality, 
productEquality, 
promote_hyp, 
hypothesis_subsumption, 
applyLambdaEquality, 
dependent_set_memberEquality, 
addEquality, 
instantiate, 
imageElimination, 
equalityElimination, 
universeEquality, 
inlEquality, 
pointwiseFunctionality, 
baseApply, 
closedConclusion, 
inrFormation
Latex:
\mforall{}[T:Type].  \mforall{}[L:T  List].  \mforall{}[P:\{x:T|  (x  \mmember{}  L)\}    {}\mrightarrow{}  \mBbbB{}].
    (l\_find(L;P)  \mmember{}  (\mexists{}x:T  [(\mexists{}i:\mBbbN{}||L||.  ((x  =  L[i])  \mwedge{}  (\muparrow{}(P  x))  \mwedge{}  (\mforall{}j:\mBbbN{}i.  (\mneg{}\muparrow{}(P  L[j])))))])
      \mvee{}  (\mdownarrow{}\mforall{}i:\mBbbN{}||L||.  (\mneg{}\muparrow{}(P  L[i]))))
Date html generated:
2018_05_21-PM-06_36_00
Last ObjectModification:
2017_07_26-PM-04_52_43
Theory : general
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