Nuprl Lemma : bag-bind-filter
∀[A,B:Type]. ∀[p:A ⟶ 𝔹]. ∀[f:{a:A| ↑p[a]}  ⟶ bag(B)]. ∀[ba:bag(A)].
  (bag-bind([a∈ba|p[a]];λa.f[a]) = bag-bind(ba;λa.if p[a] then f[a] else {} fi ) ∈ bag(B))
Proof
Definitions occuring in Statement : 
bag-bind: bag-bind(bs;f), 
bag-filter: [x∈b|p[x]], 
empty-bag: {}, 
bag: bag(T), 
assert: ↑b, 
ifthenelse: if b then t else f fi , 
bool: 𝔹, 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
set: {x:A| B[x]} , 
lambda: λx.A[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-bind: bag-bind(bs;f), 
bag: bag(T), 
quotient: x,y:A//B[x; y], 
and: P ∧ Q, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
prop: ℙ, 
so_apply: x[s], 
empty-bag: {}, 
bag-map: bag-map(f;bs), 
bag-union: bag-union(bbs), 
bag-filter: [x∈b|p[x]], 
concat: concat(ll), 
nat: ℕ, 
false: False, 
ge: i ≥ j , 
uimplies: b supposing a, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
not: ¬A, 
top: Top, 
subtype_rel: A ⊆r B, 
guard: {T}, 
or: P ∨ Q, 
cons: [a / b], 
colength: colength(L), 
so_lambda: λ2x y.t[x; y], 
so_apply: x[s1;s2], 
decidable: Dec(P), 
nil: [], 
it: ⋅, 
so_lambda: λ2x.t[x], 
sq_type: SQType(T), 
less_than: a < b, 
squash: ↓T, 
less_than': less_than'(a;b), 
bool: 𝔹, 
unit: Unit, 
btrue: tt, 
uiff: uiff(P;Q), 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
bnot: ¬bb, 
assert: ↑b, 
append: as @ bs, 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
so_apply: x[s1;s2;s3], 
bag-append: as + bs, 
true: True, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q
Lemmas referenced : 
bag_wf, 
list_wf, 
permutation_wf, 
equal_wf, 
equal-wf-base, 
assert_wf, 
bool_wf, 
nat_properties, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
ge_wf, 
less_than_wf, 
equal-wf-T-base, 
nat_wf, 
colength_wf_list, 
less_than_transitivity1, 
less_than_irreflexivity, 
list-cases, 
filter_nil_lemma, 
map_nil_lemma, 
reduce_nil_lemma, 
product_subtype_list, 
spread_cons_lemma, 
intformeq_wf, 
itermAdd_wf, 
int_formula_prop_eq_lemma, 
int_term_value_add_lemma, 
decidable__le, 
intformnot_wf, 
int_formula_prop_not_lemma, 
le_wf, 
subtract_wf, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
subtype_base_sq, 
set_subtype_base, 
int_subtype_base, 
decidable__equal_int, 
filter_cons_lemma, 
map_cons_lemma, 
reduce_cons_lemma, 
empty-bag_wf, 
eqtt_to_assert, 
eqff_to_assert, 
bool_cases_sqequal, 
bool_subtype_base, 
assert-bnot, 
list_ind_nil_lemma, 
squash_wf, 
true_wf, 
bag-append_wf, 
iff_weakening_equal, 
quotient-member-eq, 
permutation-equiv, 
bag-union_wf, 
bag-map_wf, 
list-subtype-bag
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalHypSubstitution, 
pointwiseFunctionalityForEquality, 
extract_by_obid, 
isectElimination, 
thin, 
cumulativity, 
hypothesisEquality, 
hypothesis, 
sqequalRule, 
pertypeElimination, 
productElimination, 
equalityTransitivity, 
equalitySymmetry, 
lambdaFormation, 
because_Cache, 
rename, 
dependent_functionElimination, 
independent_functionElimination, 
productEquality, 
isect_memberEquality, 
axiomEquality, 
functionEquality, 
setEquality, 
applyEquality, 
functionExtensionality, 
hyp_replacement, 
applyLambdaEquality, 
setElimination, 
intWeakElimination, 
natural_numberEquality, 
independent_isectElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
unionElimination, 
promote_hyp, 
hypothesis_subsumption, 
dependent_set_memberEquality, 
addEquality, 
baseClosed, 
instantiate, 
imageElimination, 
equalityElimination, 
universeEquality, 
imageMemberEquality
Latex:
\mforall{}[A,B:Type].  \mforall{}[p:A  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[f:\{a:A|  \muparrow{}p[a]\}    {}\mrightarrow{}  bag(B)].  \mforall{}[ba:bag(A)].
    (bag-bind([a\mmember{}ba|p[a]];\mlambda{}a.f[a])  =  bag-bind(ba;\mlambda{}a.if  p[a]  then  f[a]  else  \{\}  fi  ))
Date html generated:
2017_10_01-AM-09_06_19
Last ObjectModification:
2017_07_26-PM-04_46_27
Theory : bags
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