Nuprl Lemma : sub-bag-filter
∀[T:Type]. ∀p:T ⟶ 𝔹. ∀b,c:bag(T).  (sub-bag(T;b;[x∈c|p[x]]) 
⇐⇒ sub-bag(T;b;c) ∧ (∀x:T. (x ↓∈ b 
⇒ (↑p[x]))))
Proof
Definitions occuring in Statement : 
bag-member: x ↓∈ bs
, 
sub-bag: sub-bag(T;as;bs)
, 
bag-filter: [x∈b|p[x]]
, 
bag: bag(T)
, 
assert: ↑b
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
cand: A c∧ B
, 
member: t ∈ T
, 
so_apply: x[s]
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
subtype_rel: A ⊆r B
, 
rev_implies: P 
⇐ Q
, 
uimplies: b supposing a
, 
uiff: uiff(P;Q)
, 
sub-bag: sub-bag(T;as;bs)
, 
exists: ∃x:A. B[x]
, 
top: Top
, 
respects-equality: respects-equality(S;T)
, 
true: True
, 
squash: ↓T
, 
guard: {T}
Lemmas referenced : 
assert_witness, 
bag-member_wf, 
sub-bag_wf, 
bag-filter_wf, 
istype-assert, 
bag_wf, 
bool_wf, 
istype-universe, 
bag-split, 
sub-bag-append-trivial1, 
bnot_wf, 
sub-bag-member, 
bag-member-filter, 
equal_wf, 
subtype_rel_bag, 
assert_wf, 
bag-filter-append, 
istype-void, 
bag-append_wf, 
respects-equality-bag, 
subtype-respects-equality, 
bag-filter-trivial2, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
lambdaFormation_alt, 
independent_pairFormation, 
cut, 
hypothesis, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
applyEquality, 
hypothesisEquality, 
independent_functionElimination, 
universeIsType, 
because_Cache, 
sqequalRule, 
lambdaEquality_alt, 
productElimination, 
productIsType, 
functionIsType, 
inhabitedIsType, 
instantiate, 
universeEquality, 
dependent_functionElimination, 
hyp_replacement, 
equalitySymmetry, 
applyLambdaEquality, 
independent_isectElimination, 
equalityTransitivity, 
setEquality, 
setElimination, 
rename, 
setIsType, 
isect_memberEquality_alt, 
voidElimination, 
dependent_pairFormation_alt, 
equalityIstype, 
productEquality, 
natural_numberEquality, 
imageElimination, 
imageMemberEquality, 
baseClosed
Latex:
\mforall{}[T:Type]
    \mforall{}p:T  {}\mrightarrow{}  \mBbbB{}.  \mforall{}b,c:bag(T).
        (sub-bag(T;b;[x\mmember{}c|p[x]])  \mLeftarrow{}{}\mRightarrow{}  sub-bag(T;b;c)  \mwedge{}  (\mforall{}x:T.  (x  \mdownarrow{}\mmember{}  b  {}\mRightarrow{}  (\muparrow{}p[x]))))
Date html generated:
2019_10_15-AM-11_02_00
Last ObjectModification:
2018_11_30-AM-10_08_19
Theory : bags
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