Nuprl Lemma : filter_wf4

∀[T:Type]. ∀[P:T ⟶ 𝔹]. ∀[l:T List].  (filter(λx.P[x];l) ∈ {x:T| (x ∈ l) ∧ (↑P[x])}  List)


Proof




Definitions occuring in Statement :  l_member: (x ∈ l),  filter: filter(P;l),  list: T List,  assert: ↑b,  bool: 𝔹,  uall: ∀[x:A]. B[x],  so_apply: x[s],  and: P ∧ Q,  member: t ∈ T,  set: {x:A| B[x]} ,  lambda: λx.A[x],  function: x:A ⟶ B[x],  universe: Type
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  all: ∀x:A. B[x],  nat: ℕ,  implies: P ⇒ Q,  false: False,  ge: i ≥ j ,  guard: {T},  uimplies: b supposing a,  prop: ℙ,  subtype_rel: A ⊆r B,  or: P ∨ Q,  top: Top,  and: P ∧ Q,  so_apply: x[s],  cons: [a / b],  colength: colength(L),  so_lambda: λ2x y.t[x; y],  so_apply: x[s1;s2],  squash: ↓T,  sq_stable: SqStable(P),  uiff: uiff(P;Q),  le: A ≤ B,  not: ¬A,  less_than': less_than'(a;b),  true: True,  decidable: Dec(P),  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  subtract: n - m,  nil: [],  it: ⋅,  so_lambda: λ2x.t[x],  sq_type: SQType(T),  less_than: a < b,  bool: 𝔹,  unit: Unit,  btrue: tt,  ifthenelse: if b then t else f fi ,  cand: A c∧ B,  bfalse: ff,  exists: ∃x:A. B[x],  bnot: ¬bb,  assert: ↑b
Lemmas referenced :  nat_properties,  less_than_transitivity1,  less_than_irreflexivity,  ge_wf,  less_than_wf,  equal-wf-T-base,  nat_wf,  colength_wf_list,  list-cases,  filter_nil_lemma,  nil_wf,  l_member_wf,  assert_wf,  product_subtype_list,  spread_cons_lemma,  sq_stable__le,  le_antisymmetry_iff,  add_functionality_wrt_le,  add-associates,  add-zero,  zero-add,  le-add-cancel,  decidable__le,  false_wf,  not-le-2,  condition-implies-le,  minus-add,  minus-one-mul,  minus-one-mul-top,  add-commutes,  le_wf,  equal_wf,  subtract_wf,  not-ge-2,  less-iff-le,  minus-minus,  add-swap,  subtype_base_sq,  set_subtype_base,  int_subtype_base,  filter_cons_lemma,  bool_wf,  eqtt_to_assert,  cons_wf,  cons_member,  subtype_rel_list_set,  eqff_to_assert,  bool_cases_sqequal,  bool_subtype_base,  assert-bnot,  list_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  thin,  lambdaFormation,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  hypothesisEquality,  hypothesis,  setElimination,  rename,  sqequalRule,  intWeakElimination,  natural_numberEquality,  independent_isectElimination,  independent_functionElimination,  voidElimination,  lambdaEquality,  dependent_functionElimination,  axiomEquality,  equalityTransitivity,  equalitySymmetry,  cumulativity,  applyEquality,  because_Cache,  unionElimination,  isect_memberEquality,  voidEquality,  setEquality,  productEquality,  functionExtensionality,  promote_hyp,  hypothesis_subsumption,  productElimination,  applyLambdaEquality,  imageMemberEquality,  baseClosed,  imageElimination,  addEquality,  dependent_set_memberEquality,  independent_pairFormation,  minusEquality,  intEquality,  instantiate,  equalityElimination,  inlFormation,  inrFormation,  dependent_pairFormation,  functionEquality,  universeEquality

Latex:
\mforall{}[T:Type].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[l:T  List].    (filter(\mlambda{}x.P[x];l)  \mmember{}  \{x:T|  (x  \mmember{}  l)  \mwedge{}  (\muparrow{}P[x])\}    List)



Date html generated: 2017_04_14-AM-08_51_49
Last ObjectModification: 2017_02_27-PM-03_37_34

Theory : list_0


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