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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