Nuprl Lemma : bag-mapfilter-combine
∀[A,B,C:Type]. ∀[b:bag(A)]. ∀[f:A ⟶ bag(B)]. ∀[P:B ⟶ 𝔹]. ∀[g:{x:B| ↑P[x]}  ⟶ C].
  (bag-mapfilter(g;P;⋃x∈b.f[x]) = ⋃x∈b.bag-mapfilter(g;P;f[x]) ∈ bag(C))
Proof
Definitions occuring in Statement : 
bag-combine: ⋃x∈bs.f[x]
, 
bag-mapfilter: bag-mapfilter(f;P;bs)
, 
bag: bag(T)
, 
assert: ↑b
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
set: {x:A| B[x]} 
, 
function: x:A ⟶ B[x]
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
bag-mapfilter: bag-mapfilter(f;P;bs)
, 
so_apply: x[s]
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
true: True
, 
squash: ↓T
, 
subtype_rel: A ⊆r B
, 
uimplies: b supposing a
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
Lemmas referenced : 
assert_wf, 
bool_wf, 
bag_wf, 
set_wf, 
bag-combine_wf, 
bag-map_wf, 
bag-filter_wf, 
equal_wf, 
squash_wf, 
true_wf, 
bag-filter-combine2, 
iff_weakening_equal, 
bag-map-combine
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalRule, 
hypothesis, 
functionEquality, 
setEquality, 
cumulativity, 
hypothesisEquality, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
applyEquality, 
functionExtensionality, 
isect_memberEquality, 
axiomEquality, 
because_Cache, 
universeEquality, 
lambdaEquality, 
natural_numberEquality, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
imageMemberEquality, 
baseClosed, 
independent_isectElimination, 
productElimination, 
independent_functionElimination
Latex:
\mforall{}[A,B,C:Type].  \mforall{}[b:bag(A)].  \mforall{}[f:A  {}\mrightarrow{}  bag(B)].  \mforall{}[P:B  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[g:\{x:B|  \muparrow{}P[x]\}    {}\mrightarrow{}  C].
    (bag-mapfilter(g;P;\mcup{}x\mmember{}b.f[x])  =  \mcup{}x\mmember{}b.bag-mapfilter(g;P;f[x]))
Date html generated:
2017_10_01-AM-08_58_19
Last ObjectModification:
2017_07_26-PM-04_40_18
Theory : bags
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