Nuprl Lemma : filter-union

∀[T:Type]. ∀eq:EqDecider(T). ∀as,bs:T List. ∀P:T ⟶ 𝔹.  (filter(P;as ⋃ bs) = filter(P;as) ⋃ filter(P;bs) ∈ (T List))


Proof




Definitions occuring in Statement :  l-union: as ⋃ bs,  filter: filter(P;l),  list: T List,  deq: EqDecider(T),  bool: 𝔹,  uall: ∀[x:A]. B[x],  all: ∀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,  all: ∀x:A. B[x],  l-union: as ⋃ bs,  so_lambda: λ2x.t[x],  subtype_rel: A ⊆r B,  so_apply: x[s],  prop: ℙ,  uimplies: b supposing a,  implies: P ⇒ Q,  top: Top,  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  uiff: uiff(P;Q),  and: P ∧ Q,  ifthenelse: if b then t else f fi ,  bfalse: ff,  exists: ∃x:A. B[x],  or: P ∨ Q,  sq_type: SQType(T),  guard: {T},  bnot: ¬bb,  assert: ↑b,  false: False,  squash: ↓T,  not: ¬A,  iff: P ⇐⇒ Q,  true: True,  rev_implies: P ⇐ Q,  cand: A c∧ B
Lemmas referenced :  list_induction,  equal_wf,  list_wf,  filter_wf5,  reduce_wf,  insert_wf,  subtype_rel_dep_function,  bool_wf,  l_member_wf,  subtype_rel_self,  set_wf,  reduce_nil_lemma,  filter_nil_lemma,  reduce_cons_lemma,  filter_cons_lemma,  eqtt_to_assert,  eqff_to_assert,  bool_cases_sqequal,  subtype_base_sq,  bool_subtype_base,  assert-bnot,  deq_wf,  insert-cases2,  squash_wf,  true_wf,  ite_rw_false,  cons_wf,  member_filter_2,  assert_wf,  iff_weakening_equal,  member_filter
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  lambdaFormation,  thin,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  hypothesisEquality,  sqequalRule,  lambdaEquality,  cumulativity,  hypothesis,  because_Cache,  applyEquality,  setEquality,  independent_isectElimination,  setElimination,  rename,  independent_functionElimination,  dependent_functionElimination,  isect_memberEquality,  voidElimination,  voidEquality,  functionExtensionality,  unionElimination,  equalityElimination,  equalityTransitivity,  equalitySymmetry,  productElimination,  dependent_pairFormation,  promote_hyp,  instantiate,  functionEquality,  axiomEquality,  universeEquality,  hyp_replacement,  applyLambdaEquality,  imageElimination,  equalityUniverse,  levelHypothesis,  natural_numberEquality,  imageMemberEquality,  baseClosed,  independent_pairFormation

Latex:
\mforall{}[T:Type]
    \mforall{}eq:EqDecider(T).  \mforall{}as,bs:T  List.  \mforall{}P:T  {}\mrightarrow{}  \mBbbB{}.    (filter(P;as  \mcup{}  bs)  =  filter(P;as)  \mcup{}  filter(P;bs))



Date html generated: 2017_04_17-AM-09_09_50
Last ObjectModification: 2017_02_27-PM-05_17_56

Theory : decidable!equality


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