Nuprl Lemma : bar-induction

∀[T:Type]. ∀[R,A:(T List) ⟶ ℙ].
  ((∀s:T List. Dec(R[s]))
  ⇒ (∀s:T List. (R[s] ⇒ A[s]))
  ⇒ (∀s:T List. ((∀t:T. A[s @ [t]]) ⇒ A[s]))
  ⇒ (∀s:T List. ((∀alpha:ℕ ⟶ T. (↓∃n:ℕ. R[s @ map(alpha;upto(n))])) ⇒ A[s])))


Proof




Definitions occuring in Statement :  upto: upto(n),  map: map(f;as),  append: as @ bs,  cons: [a / b],  nil: [],  list: T List,  nat: ℕ,  decidable: Dec(P),  uall: ∀[x:A]. B[x],  prop: ℙ,  so_apply: x[s],  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  squash: ↓T,  implies: P ⇒ Q,  function: x:A ⟶ B[x],  universe: Type
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  implies: P ⇒ Q,  all: ∀x:A. B[x],  member: t ∈ T,  so_apply: x[s],  nat: ℕ,  so_apply: x[s1;s2],  prop: ℙ,  so_lambda: λ2x.t[x],  subtype_rel: A ⊆r B,  uimplies: b supposing a,  le: A ≤ B,  and: P ∧ Q,  less_than': less_than'(a;b),  false: False,  not: ¬A,  guard: {T},  top: Top,  ge: i ≥ j ,  decidable: Dec(P),  or: P ∨ Q,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  int_seg: {i..j-},  lelt: i ≤ j < k,  squash: ↓T,  true: True,  iff: P ⇐⇒ Q,  seq-adjoin: s++t,  seq-append: seq-append(n;m;s1;s2),  less_than: a < b,  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  uiff: uiff(P;Q),  ifthenelse: if b then t else f fi ,  label: ...$L... t,  rev_implies: P ⇐ Q,  bfalse: ff,  sq_type: SQType(T),  bnot: ¬bb,  assert: ↑b,  cand: A c∧ B
Lemmas referenced :  bar_induction,  list_wf,  map_wf,  int_seg_wf,  upto_wf,  nat_wf,  all_wf,  seq-adjoin_wf,  squash_wf,  exists_wf,  append_wf,  subtype_rel_dep_function,  int_seg_subtype_nat,  false_wf,  cons_wf,  nil_wf,  decidable_wf,  list_extensionality,  length-append,  map-length,  length_of_cons_lemma,  length_of_nil_lemma,  length_upto,  nat_properties,  decidable__le,  satisfiable-full-omega-tt,  intformand_wf,  intformnot_wf,  intformle_wf,  itermConstant_wf,  itermAdd_wf,  itermVar_wf,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_le_lemma,  int_term_value_constant_lemma,  int_term_value_add_lemma,  int_term_value_var_lemma,  int_formula_prop_wf,  le_wf,  select-map,  subtype_rel_list,  top_wf,  less_than_wf,  true_wf,  length_append,  iff_weakening_equal,  add_functionality_wrt_eq,  length_wf,  map_length_nat,  length-singleton,  lelt_wf,  length-map,  intformless_wf,  int_formula_prop_less_lemma,  lt_int_wf,  bool_wf,  eqtt_to_assert,  assert_of_lt_int,  equal_wf,  select_upto,  decidable__equal_int,  intformeq_wf,  int_formula_prop_eq_lemma,  decidable__lt,  eqff_to_assert,  bool_cases_sqequal,  subtype_base_sq,  bool_subtype_base,  assert-bnot,  select-cons-hd,  subtract_wf,  itermSubtract_wf,  int_term_value_subtract_lemma,  select-append,  select-upto,  length_wf_nat,  select_wf,  int_seg_properties,  seq-append_wf,  add_nat_wf,  add-is-int-iff,  non_neg_length
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  lambdaFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  sqequalRule,  hypothesisEquality,  lambdaEquality,  applyEquality,  functionExtensionality,  cumulativity,  hypothesis,  natural_numberEquality,  setElimination,  rename,  because_Cache,  functionEquality,  independent_functionElimination,  dependent_functionElimination,  addEquality,  independent_isectElimination,  independent_pairFormation,  universeEquality,  hyp_replacement,  equalitySymmetry,  isect_memberEquality,  voidElimination,  voidEquality,  dependent_set_memberEquality,  unionElimination,  dependent_pairFormation,  int_eqEquality,  intEquality,  computeAll,  imageElimination,  equalityTransitivity,  productElimination,  imageMemberEquality,  baseClosed,  lessCases,  sqequalAxiom,  equalityElimination,  promote_hyp,  instantiate,  applyLambdaEquality,  pointwiseFunctionality,  baseApply,  closedConclusion

Latex:
\mforall{}[T:Type].  \mforall{}[R,A:(T  List)  {}\mrightarrow{}  \mBbbP{}].
    ((\mforall{}s:T  List.  Dec(R[s]))
    {}\mRightarrow{}  (\mforall{}s:T  List.  (R[s]  {}\mRightarrow{}  A[s]))
    {}\mRightarrow{}  (\mforall{}s:T  List.  ((\mforall{}t:T.  A[s  @  [t]])  {}\mRightarrow{}  A[s]))
    {}\mRightarrow{}  (\mforall{}s:T  List.  ((\mforall{}alpha:\mBbbN{}  {}\mrightarrow{}  T.  (\mdownarrow{}\mexists{}n:\mBbbN{}.  R[s  @  map(alpha;upto(n))]))  {}\mRightarrow{}  A[s])))



Date html generated: 2017_04_17-AM-08_59_46
Last ObjectModification: 2017_02_27-PM-05_16_39

Theory : list_1


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