Nuprl Lemma : find-first_wf
∀[T:Type]. ∀[L:T List]. ∀[P:{x:T| (x ∈ L)}  ⟶ 𝔹].  (find-first(P;L) ∈ (∃x:T [first-member(T;x;L;P)]) ∨ (∀x∈L.¬↑(P x)))
Proof
Definitions occuring in Statement : 
find-first: find-first(P;L)
, 
first-member: first-member(T;x;L;P)
, 
l_all: (∀x∈L.P[x])
, 
l_member: (x ∈ l)
, 
list: T List
, 
assert: ↑b
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
sq_exists: ∃x:A [B[x]]
, 
not: ¬A
, 
or: P ∨ Q
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
find-first: find-first(P;L)
, 
prop: ℙ
, 
can-find-first-ext, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
first-member: first-member(T;x;L;P)
, 
subtype_rel: A ⊆r B
, 
or: P ∨ Q
, 
so_lambda: λ2x.t[x]
, 
and: P ∧ Q
, 
int_seg: {i..j-}
, 
uimplies: b supposing a
, 
guard: {T}
, 
lelt: i ≤ j < k
, 
decidable: Dec(P)
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
top: Top
, 
less_than: a < b
, 
squash: ↓T
, 
l_member: (x ∈ l)
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
cand: A c∧ B
, 
nat: ℕ
, 
ge: i ≥ j 
, 
so_apply: x[s]
, 
sq_exists: ∃x:A [B[x]]
Lemmas referenced : 
istype-universe, 
l_member_wf, 
bool_wf, 
list_wf, 
can-find-first-ext, 
sq_exists_wf, 
exists_wf, 
int_seg_wf, 
length_wf, 
equal_wf, 
select_wf, 
int_seg_properties, 
decidable__le, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
decidable__lt, 
intformless_wf, 
int_formula_prop_less_lemma, 
assert_wf, 
int_seg_subtype_nat, 
istype-false, 
less_than_wf, 
nat_properties, 
not_wf, 
select_member, 
le_wf, 
l_all_wf2
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
cut, 
sqequalHypSubstitution, 
hypothesis, 
functionIsType, 
setIsType, 
introduction, 
extract_by_obid, 
isectElimination, 
thin, 
hypothesisEquality, 
universeIsType, 
universeEquality, 
sqequalRule, 
instantiate, 
inhabitedIsType, 
lambdaFormation_alt, 
equalityIsType1, 
equalityTransitivity, 
equalitySymmetry, 
dependent_functionElimination, 
independent_functionElimination, 
applyEquality, 
lambdaEquality_alt, 
isectIsType, 
unionIsType, 
natural_numberEquality, 
productEquality, 
because_Cache, 
setElimination, 
rename, 
independent_isectElimination, 
productElimination, 
unionElimination, 
approximateComputation, 
dependent_pairFormation_alt, 
int_eqEquality, 
isect_memberEquality_alt, 
voidElimination, 
independent_pairFormation, 
imageElimination, 
productIsType, 
dependent_set_memberEquality_alt, 
functionEquality
Latex:
\mforall{}[T:Type].  \mforall{}[L:T  List].  \mforall{}[P:\{x:T|  (x  \mmember{}  L)\}    {}\mrightarrow{}  \mBbbB{}].
    (find-first(P;L)  \mmember{}  (\mexists{}x:T  [first-member(T;x;L;P)])  \mvee{}  (\mforall{}x\mmember{}L.\mneg{}\muparrow{}(P  x)))
Date html generated:
2019_10_15-AM-11_08_07
Last ObjectModification:
2018_10_09-PM-03_14_28
Theory : general
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