Nuprl Lemma : filter-index_wf

∀[T:Type]. ∀[P:T ⟶ 𝔹]. ∀[L:T List].  (filter-index(P;L) ∈ i:{i:ℕ||L||| ↑(P L[i])}  ⟶ {j:ℕ||filter(P;L)||| filter(P;L)[\000Cj] = L[i] ∈ T} )


Proof




Definitions occuring in Statement :  filter-index: filter-index(P;L),  select: L[n],  length: ||as||,  filter: filter(P;l),  list: T List,  int_seg: {i..j-},  assert: ↑b,  bool: 𝔹,  uall: ∀[x:A]. B[x],  member: t ∈ T,  set: {x:A| B[x]} ,  apply: f a,  function: x:A ⟶ B[x],  natural_number: $n,  universe: Type,  equal: s = t ∈ T
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 ,  uimplies: b supposing a,  not: ¬A,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  and: P ∧ Q,  prop: ℙ,  or: P ∨ Q,  select: L[n],  nil: [],  it: ⋅,  so_lambda: λ2x y.t[x; y],  so_apply: x[s1;s2],  cons: [a / b],  le: A ≤ B,  less_than': less_than'(a;b),  colength: colength(L),  guard: {T},  so_lambda: λ2x.t[x],  so_apply: x[s],  sq_type: SQType(T),  less_than: a < b,  squash: ↓T,  decidable: Dec(P),  subtype_rel: A ⊆r B,  int_seg: {i..j-},  lelt: i ≤ j < k,  filter-index: filter-index(P;L),  so_lambda: so_lambda3,  so_apply: x[s1;s2;s3],  eq_int: (i =z j),  subtract: n - m,  ifthenelse: if b then t else f fi ,  btrue: tt,  istype: istype(T),  nat_plus: ℕ+,  uiff: uiff(P;Q),  bool: 𝔹,  unit: Unit,  bfalse: ff,  bnot: ¬bb,  assert: ↑b,  nequal: a ≠ b ∈ T ,  true: True,  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q
Lemmas referenced :  void_wf,  nat_properties,  full-omega-unsat,  intformand_wf,  intformle_wf,  itermConstant_wf,  itermVar_wf,  intformless_wf,  istype-int,  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,  istype-less_than,  list-cases,  length_of_nil_lemma,  stuck-spread,  istype-base,  filter_nil_lemma,  int_seg_wf,  product_subtype_list,  colength-cons-not-zero,  colength_wf_list,  istype-void,  istype-le,  subtract-1-ge-0,  subtype_base_sq,  intformeq_wf,  int_formula_prop_eq_lemma,  set_subtype_base,  int_subtype_base,  spread_cons_lemma,  decidable__equal_int,  subtract_wf,  intformnot_wf,  itermSubtract_wf,  itermAdd_wf,  int_formula_prop_not_lemma,  int_term_value_subtract_lemma,  int_term_value_add_lemma,  decidable__le,  le_wf,  length_of_cons_lemma,  filter_cons_lemma,  length_wf,  istype-nat,  istype-assert,  select_wf,  int_seg_properties,  decidable__lt,  list_wf,  bool_wf,  istype-universe,  list_ind_cons_lemma,  istype-false,  add_nat_plus,  length_wf_nat,  filter_wf5,  subtype_rel_dep_function,  l_member_wf,  nat_plus_properties,  add-is-int-iff,  false_wf,  cons_wf,  non_neg_length,  assert_functionality_wrt_uiff,  select_cons_tl,  eq_int_wf,  eqtt_to_assert,  assert_of_eq_int,  eqff_to_assert,  bool_cases_sqequal,  bool_subtype_base,  assert-bnot,  neg_assert_of_eq_int,  add-member-int_seg2,  ifthenelse_wf,  select_cons_tl_sq2,  int_seg_subtype_nat,  equal_wf,  squash_wf,  true_wf,  subtype_rel_self,  iff_weakening_equal,  select-cons-tl,  equal-wf-T-base,  assert_wf,  bnot_wf,  not_wf,  add-zero,  uiff_transitivity,  assert_of_bnot
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation_alt,  introduction,  cut,  functionExtensionality,  voidElimination,  thin,  instantiate,  extract_by_obid,  hypothesis,  functionExtensionality_alt,  setElimination,  rename,  lambdaFormation_alt,  sqequalHypSubstitution,  isectElimination,  hypothesisEquality,  sqequalRule,  intWeakElimination,  natural_numberEquality,  independent_isectElimination,  approximateComputation,  independent_functionElimination,  dependent_pairFormation_alt,  lambdaEquality_alt,  int_eqEquality,  dependent_functionElimination,  Error :memTop,  independent_pairFormation,  universeIsType,  axiomEquality,  equalityTransitivity,  equalitySymmetry,  functionIsTypeImplies,  inhabitedIsType,  unionElimination,  baseClosed,  promote_hyp,  hypothesis_subsumption,  productElimination,  equalityIstype,  because_Cache,  dependent_set_memberEquality_alt,  applyLambdaEquality,  imageElimination,  baseApply,  closedConclusion,  applyEquality,  intEquality,  sqequalBase,  addEquality,  setIsType,  isect_memberEquality_alt,  isectIsTypeImplies,  functionIsType,  universeEquality,  cumulativity,  setEquality,  pointwiseFunctionality,  productIsType,  equalityElimination,  minusEquality,  imageMemberEquality

Latex:
\mforall{}[T:Type].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[L:T  List].
    (filter-index(P;L)  \mmember{}  i:\{i:\mBbbN{}||L|||  \muparrow{}(P  L[i])\}    {}\mrightarrow{}  \{j:\mBbbN{}||filter(P;L)|||  filter(P;L)[j]  =  L[i]\}  )



Date html generated: 2020_05_19-PM-09_42_29
Last ObjectModification: 2019_12_31-PM-00_12_36

Theory : list_1


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