Nuprl Lemma : filter_is_empty
∀[T:Type]. ∀[P:T ⟶ 𝔹]. ∀[L:T List].  uiff(↑null(filter(P;L));∀[i:ℕ||L||]. (¬↑(P L[i])))
Proof
Definitions occuring in Statement : 
select: L[n]
, 
length: ||as||
, 
null: null(as)
, 
filter: filter(P;l)
, 
list: T List
, 
int_seg: {i..j-}
, 
assert: ↑b
, 
bool: 𝔹
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
not: ¬A
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
natural_number: $n
, 
universe: Type
Definitions unfolded in proof : 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
int_seg: {i..j-}
, 
uimplies: b supposing a
, 
guard: {T}
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
all: ∀x:A. B[x]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
top: Top
, 
prop: ℙ
, 
less_than: a < b
, 
squash: ↓T
, 
subtype_rel: A ⊆r B
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
uiff: uiff(P;Q)
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
bfalse: ff
, 
true: True
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
l_all: (∀x∈L.P[x])
Lemmas referenced : 
assert_wf, 
select_wf, 
int_seg_properties, 
length_wf, 
decidable__le, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
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, 
int_seg_wf, 
null_wf, 
filter_wf5, 
subtype_rel_dep_function, 
bool_wf, 
l_member_wf, 
subtype_rel_self, 
set_wf, 
uall_wf, 
not_wf, 
list_wf, 
assert_witness, 
null_cons_lemma, 
false_wf, 
true_wf, 
l_all_wf, 
equal-wf-T-base, 
bnot_wf, 
list_induction, 
iff_wf, 
filter_nil_lemma, 
null_nil_lemma, 
l_all_nil, 
l_all_wf_nil, 
filter_cons_lemma, 
eqtt_to_assert, 
uiff_transitivity, 
eqff_to_assert, 
assert_of_bnot, 
equal_wf, 
l_all_cons, 
ifthenelse_wf, 
cons_wf, 
satisfiable-full-omega-tt
Rules used in proof : 
cut, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
applyEquality, 
functionExtensionality, 
hypothesisEquality, 
cumulativity, 
because_Cache, 
setElimination, 
rename, 
hypothesis, 
independent_isectElimination, 
natural_numberEquality, 
productElimination, 
dependent_functionElimination, 
unionElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
sqequalRule, 
independent_pairFormation, 
imageElimination, 
setEquality, 
lambdaFormation, 
functionEquality, 
universeEquality, 
isect_memberFormation, 
independent_pairEquality, 
equalityTransitivity, 
equalitySymmetry, 
productEquality, 
baseClosed, 
equalityElimination, 
computeAll
Latex:
\mforall{}[T:Type].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[L:T  List].    uiff(\muparrow{}null(filter(P;L));\mforall{}[i:\mBbbN{}||L||].  (\mneg{}\muparrow{}(P  L[i])))
Date html generated:
2019_06_20-PM-01_25_50
Last ObjectModification:
2018_09_17-PM-10_26_04
Theory : list_1
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