Nuprl Lemma : bag-filter-trivial2
∀[T:Type]. ∀[p:T ⟶ 𝔹]. ∀[bs:bag(T)].  [x∈bs|p[x]] = bs ∈ bag(T) supposing ∀x:T. (x ↓∈ bs ⇒ (↑p[x]))
Proof
Definitions occuring in Statement : 
bag-member: x ↓∈ bs, 
bag-filter: [x∈b|p[x]], 
bag: bag(T), 
assert: ↑b, 
bool: 𝔹, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
function: x:A ⟶ B[x], 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
squash: ↓T, 
exists: ∃x:A. B[x], 
prop: ℙ, 
so_lambda: λ2x.t[x], 
implies: P ⇒ Q, 
so_apply: x[s], 
bag-filter: [x∈b|p[x]], 
bag: bag(T), 
so_lambda: λ2x y.t[x; y], 
so_apply: x[s1;s2], 
uimplies: b supposing a, 
all: ∀x:A. B[x], 
subtype_rel: A ⊆r B, 
top: Top, 
cons-bag: x.b, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
rev_uimplies: rev_uimplies(P;Q), 
sq_or: a ↓∨ b, 
or: P ∨ Q, 
assert: ↑b, 
ifthenelse: if b then t else f fi , 
btrue: tt, 
iff: P ⇐⇒ Q, 
true: True, 
rev_implies: P ⇐ Q, 
sq_type: SQType(T), 
guard: {T}
Lemmas referenced : 
bag_to_squash_list, 
all_wf, 
bag-member_wf, 
assert_wf, 
quotient-member-eq, 
list_wf, 
permutation_wf, 
permutation-equiv, 
filter_wf5, 
l_member_wf, 
list_induction, 
list-subtype-bag, 
filter_nil_lemma, 
permutation-nil, 
nil_wf, 
filter_cons_lemma, 
bag-member-cons, 
cons_wf, 
equal_wf, 
bag_wf, 
bag-filter_wf, 
subtype_rel_bag, 
bool_wf, 
subtype_base_sq, 
bool_subtype_base, 
iff_imp_equal_bool, 
btrue_wf, 
true_wf, 
permutation-cons2
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isectElimination, 
thin, 
hypothesisEquality, 
imageElimination, 
productElimination, 
promote_hyp, 
hypothesis, 
equalitySymmetry, 
hyp_replacement, 
Error :applyLambdaEquality, 
cumulativity, 
sqequalRule, 
lambdaEquality, 
functionEquality, 
applyEquality, 
functionExtensionality, 
rename, 
independent_isectElimination, 
dependent_functionElimination, 
setElimination, 
setEquality, 
independent_functionElimination, 
because_Cache, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
lambdaFormation, 
inlFormation, 
imageMemberEquality, 
baseClosed, 
universeEquality, 
isect_memberFormation, 
axiomEquality, 
equalityTransitivity, 
instantiate, 
independent_pairFormation, 
natural_numberEquality, 
inrFormation
Latex:
\mforall{}[T:Type].  \mforall{}[p:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[bs:bag(T)].    [x\mmember{}bs|p[x]]  =  bs  supposing  \mforall{}x:T.  (x  \mdownarrow{}\mmember{}  bs  {}\mRightarrow{}  (\muparrow{}p[x]))
 Date html generated: 
2016_10_25-AM-10_30_14
 Last ObjectModification: 
2016_07_12-AM-06_46_17
Theory : bags
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