Nuprl Lemma : int-list-index-property

∀x:ℤ. ∀L:ℤ List.  (((x ∈ L) ⇐⇒ int-list-index(L;x) < ||L||) ∧ ((x ∈ L) ⇒ (L[int-list-index(L;x)] = x ∈ ℤ)))


Proof




Definitions occuring in Statement :  int-list-index: int-list-index(L;x),  l_member: (x ∈ l),  select: L[n],  length: ||as||,  list: T List,  less_than: a < b,  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  implies: P ⇒ Q,  and: P ∧ Q,  int: ℤ,  equal: s = t ∈ T
Definitions unfolded in proof :  all: ∀x:A. B[x],  uall: ∀[x:A]. B[x],  member: t ∈ T,  so_lambda: λ2x.t[x],  prop: ℙ,  and: P ∧ Q,  subtype_rel: A ⊆r B,  int_seg: {i..j-},  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  implies: P ⇒ Q,  uimplies: b supposing a,  so_apply: x[s],  select: L[n],  nil: [],  it: ⋅,  so_lambda: λ2x y.t[x; y],  top: Top,  so_apply: x[s1;s2],  cand: A c∧ B,  not: ¬A,  false: False,  ge: i ≥ j ,  guard: {T},  lelt: i ≤ j < k,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  int-list-index: int-list-index(L;x),  so_lambda: so_lambda(x,y,z.t[x; y; z]),  so_apply: x[s1;s2;s3],  bool: 𝔹,  unit: Unit,  btrue: tt,  uiff: uiff(P;Q),  ifthenelse: if b then t else f fi ,  nat_plus: ℕ+,  less_than: a < b,  squash: ↓T,  less_than': less_than'(a;b),  true: True,  decidable: Dec(P),  or: P ∨ Q,  sq_type: SQType(T),  bfalse: ff,  bnot: ¬bb,  assert: ↑b,  nequal: a ≠ b ∈ T ,  cons: [a / b],  le: A ≤ B
Lemmas referenced :  list_induction,  iff_wf,  l_member_wf,  less_than_wf,  int-list-index_wf,  int_seg_wf,  length_wf,  equal-wf-base,  int_subtype_base,  list_subtype_base,  list_wf,  length_of_nil_lemma,  stuck-spread,  base_wf,  null_nil_lemma,  btrue_wf,  member-implies-null-eq-bfalse,  nil_wf,  btrue_neq_bfalse,  length_nil,  non_neg_length,  int_seg_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,  list_ind_cons_lemma,  length_of_cons_lemma,  eq_int_wf,  bool_wf,  eqtt_to_assert,  assert_of_eq_int,  add_nat_plus,  length_wf_nat,  nat_plus_wf,  nat_plus_properties,  decidable__lt,  add-is-int-iff,  intformnot_wf,  itermAdd_wf,  intformeq_wf,  int_formula_prop_not_lemma,  int_term_value_add_lemma,  int_formula_prop_eq_lemma,  false_wf,  equal_wf,  cons_wf,  cons_member,  subtype_base_sq,  eqff_to_assert,  bool_cases_sqequal,  bool_subtype_base,  assert-bnot,  neg_assert_of_eq_int,  select-cons-tl,  int_seg_subtype_nat,  add-subtract-cancel
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  cut,  thin,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  intEquality,  sqequalRule,  lambdaEquality,  productEquality,  hypothesisEquality,  hypothesis,  applyEquality,  setElimination,  rename,  natural_numberEquality,  addEquality,  functionEquality,  baseApply,  closedConclusion,  baseClosed,  because_Cache,  independent_isectElimination,  productElimination,  independent_functionElimination,  dependent_functionElimination,  isect_memberEquality,  voidElimination,  voidEquality,  independent_pairFormation,  equalityTransitivity,  equalitySymmetry,  applyLambdaEquality,  dependent_pairFormation,  int_eqEquality,  computeAll,  unionElimination,  equalityElimination,  dependent_set_memberEquality,  imageMemberEquality,  pointwiseFunctionality,  promote_hyp,  inlFormation,  instantiate,  cumulativity,  imageElimination,  inrFormation

Latex:
\mforall{}x:\mBbbZ{}.  \mforall{}L:\mBbbZ{}  List.
    (((x  \mmember{}  L)  \mLeftarrow{}{}\mRightarrow{}  int-list-index(L;x)  <  ||L||)  \mwedge{}  ((x  \mmember{}  L)  {}\mRightarrow{}  (L[int-list-index(L;x)]  =  x)))



Date html generated: 2018_05_21-PM-07_32_24
Last ObjectModification: 2017_07_26-PM-05_07_31

Theory : general


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