Nuprl Lemma : member-filter-witness_wf
∀[T:Type]. ∀[P:T ⟶ 𝔹]. ∀[L:T List]. ∀[x:{x:T| ↑(P x)} ].  (member-filter-witness(P;L;x) ∈ (x ∈ L) 
⇒ (x ∈ filter(P;L)))
Proof
Definitions occuring in Statement : 
member-filter-witness: member-filter-witness(P;L;x)
, 
l_member: (x ∈ l)
, 
filter: filter(P;l)
, 
list: T List
, 
assert: ↑b
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
implies: 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
, 
member-filter-witness: member-filter-witness(P;L;x)
, 
implies: P 
⇒ Q
, 
l_member: (x ∈ l)
, 
exists: ∃x:A. B[x]
, 
cand: A c∧ B
, 
prop: ℙ
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
ge: i ≥ j 
, 
all: ∀x:A. B[x]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
uimplies: b supposing a
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
false: False
, 
top: Top
, 
sq_type: SQType(T)
, 
guard: {T}
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
true: True
, 
less_than: a < b
, 
squash: ↓T
, 
subtype_rel: A ⊆r B
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
istype: istype(T)
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
it: ⋅
Lemmas referenced : 
assert_wf, 
list_wf, 
bool_wf, 
filter-index_wf, 
nat_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, 
le_wf, 
less_than_wf, 
length_wf, 
assert_elim, 
subtype_base_sq, 
bool_subtype_base, 
select_wf, 
int_seg_properties, 
decidable__lt, 
intformless_wf, 
int_formula_prop_less_lemma, 
int_seg_subtype_nat, 
filter_wf5, 
subtype_rel_dep_function, 
l_member_wf, 
istype-false, 
member-less_than, 
filter_type, 
subtype_rel_self
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
Error :lambdaEquality_alt, 
sqequalHypSubstitution, 
productElimination, 
thin, 
sqequalRule, 
hypothesis, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
Error :setIsType, 
Error :universeIsType, 
hypothesisEquality, 
extract_by_obid, 
isectElimination, 
applyEquality, 
Error :isect_memberEquality_alt, 
Error :isectIsTypeImplies, 
Error :inhabitedIsType, 
Error :functionIsType, 
universeEquality, 
Error :dependent_set_memberEquality_alt, 
setElimination, 
rename, 
independent_pairFormation, 
dependent_functionElimination, 
natural_numberEquality, 
unionElimination, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
Error :dependent_pairFormation_alt, 
int_eqEquality, 
voidElimination, 
Error :productIsType, 
Error :equalityIsType1, 
applyLambdaEquality, 
instantiate, 
cumulativity, 
because_Cache, 
imageElimination, 
Error :lambdaFormation_alt, 
Error :dependent_pairEquality_alt, 
closedConclusion, 
setEquality, 
independent_pairEquality
Latex:
\mforall{}[T:Type].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[L:T  List].  \mforall{}[x:\{x:T|  \muparrow{}(P  x)\}  ].
    (member-filter-witness(P;L;x)  \mmember{}  (x  \mmember{}  L)  {}\mRightarrow{}  (x  \mmember{}  filter(P;L)))
Date html generated:
2019_06_20-PM-01_25_12
Last ObjectModification:
2018_10_15-PM-02_35_51
Theory : list_1
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