Nuprl Lemma : l-first_wf
∀[T:Type]. ∀[f:T ⟶ 𝔹]. ∀[L:T List].  (l-first(x.f[x];L) ∈ (∃x:{T| ((x ∈ L) ∧ (↑f[x]))}) ∨ (∀x∈L.¬↑f[x]))
Proof
Definitions occuring in Statement : 
l-first: l-first(x.f[x];L)
, 
l_all: (∀x∈L.P[x])
, 
l_member: (x ∈ l)
, 
list: T List
, 
assert: ↑b
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
sq_exists: ∃x:{A| B[x]}
, 
not: ¬A
, 
or: P ∨ Q
, 
and: P ∧ Q
, 
member: t ∈ T
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
l-first: l-first(x.f[x];L)
, 
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
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
so_apply: x[s1;s2;s3]
, 
l_all: (∀x∈L.P[x])
, 
select: L[n]
, 
nil: []
, 
it: ⋅
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
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
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
exposed-it: exposed-it
, 
bool: 𝔹
, 
unit: Unit
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
ifthenelse: if b then t else f fi 
, 
cand: A c∧ B
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
bfalse: ff
, 
bnot: ¬bb
, 
assert: ↑b
, 
le: A ≤ B
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, 
equal-wf-T-base, 
nat_wf, 
colength_wf_list, 
less_than_transitivity1, 
less_than_irreflexivity, 
list-cases, 
list_ind_nil_lemma, 
stuck-spread, 
base_wf, 
length_of_nil_lemma, 
int_seg_properties, 
int_seg_wf, 
length_wf, 
nil_wf, 
sq_exists_wf, 
l_member_wf, 
assert_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, 
list_ind_cons_lemma, 
bool_wf, 
eqtt_to_assert, 
cons_member, 
cons_wf, 
l_all_wf, 
not_wf, 
eqff_to_assert, 
bool_cases_sqequal, 
bool_subtype_base, 
assert-bnot, 
or_wf, 
list_wf, 
subtype_rel_sets, 
length_of_cons_lemma, 
select_wf, 
non_neg_length, 
decidable__lt, 
select-cons, 
le_int_wf, 
bnot_wf, 
bool_cases, 
assert_of_le_int, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bnot, 
add-is-int-iff, 
false_wf, 
lelt_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
introduction, 
cut, 
thin, 
lambdaFormation, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
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, 
cumulativity, 
applyEquality, 
because_Cache, 
unionElimination, 
inrEquality, 
baseClosed, 
productElimination, 
productEquality, 
functionExtensionality, 
promote_hyp, 
hypothesis_subsumption, 
applyLambdaEquality, 
dependent_set_memberEquality, 
addEquality, 
instantiate, 
imageElimination, 
equalityElimination, 
inlEquality, 
inlFormation, 
setEquality, 
functionEquality, 
universeEquality, 
inrFormation, 
impliesFunctionality, 
pointwiseFunctionality, 
baseApply, 
closedConclusion
Latex:
\mforall{}[T:Type].  \mforall{}[f:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[L:T  List].
    (l-first(x.f[x];L)  \mmember{}  (\mexists{}x:\{T|  ((x  \mmember{}  L)  \mwedge{}  (\muparrow{}f[x]))\})  \mvee{}  (\mforall{}x\mmember{}L.\mneg{}\muparrow{}f[x]))
Date html generated:
2017_04_17-AM-07_24_49
Last ObjectModification:
2017_02_27-PM-04_03_56
Theory : list_1
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