Nuprl Lemma : nth_tl_decomp

∀[T:Type]. ∀[m:ℕ]. ∀[L:T List].  nth_tl(m;L) ~ [L[m] / nth_tl(1 + m;L)] supposing m < ||L||


Proof




Definitions occuring in Statement :  select: L[n],  length: ||as||,  nth_tl: nth_tl(n;as),  cons: [a / b],  list: T List,  nat: ℕ,  less_than: a < b,  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  add: n + m,  natural_number: $n,  universe: Type,  sqequal: s ~ t
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  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],  all: ∀x:A. B[x],  top: Top,  and: P ∧ Q,  prop: ℙ,  nth_tl: nth_tl(n;as),  le_int: i ≤z j,  lt_int: i <z j,  bnot: ¬bb,  ifthenelse: if b then t else f fi ,  bfalse: ff,  subtract: n - m,  btrue: tt,  decidable: Dec(P),  or: P ∨ Q,  squash: ↓T,  less_than: a < b,  true: True,  subtype_rel: A ⊆r B,  guard: {T},  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  bool: 𝔹,  unit: Unit,  it: ⋅,  uiff: uiff(P;Q),  sq_type: SQType(T),  assert: ↑b,  select: L[n],  nil: [],  so_lambda: λ2x y.t[x; y],  so_apply: x[s1;s2],  cons: [a / b]
Lemmas referenced :  nat_properties,  full-omega-unsat,  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,  ge_wf,  less_than_wf,  length_wf,  list_wf,  decidable__le,  subtract_wf,  intformnot_wf,  itermSubtract_wf,  int_formula_prop_not_lemma,  int_term_value_subtract_lemma,  nat_wf,  list_decomp,  select0,  tl_wf,  squash_wf,  true_wf,  length_tl,  subtype_rel_self,  iff_weakening_equal,  decidable__lt,  le_int_wf,  bool_wf,  eqtt_to_assert,  assert_of_le_int,  eqff_to_assert,  equal_wf,  bool_cases_sqequal,  subtype_base_sq,  bool_subtype_base,  assert-bnot,  le_wf,  non_neg_length,  itermAdd_wf,  int_term_value_add_lemma,  int_subtype_base,  list-cases,  reduce_tl_nil_lemma,  nth_tl_nil,  stuck-spread,  base_wf,  length_of_nil_lemma,  product_subtype_list,  reduce_tl_cons_lemma,  length_of_cons_lemma,  select-cons-tl
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  hypothesis,  setElimination,  rename,  intWeakElimination,  lambdaFormation,  natural_numberEquality,  independent_isectElimination,  approximateComputation,  independent_functionElimination,  dependent_pairFormation,  lambdaEquality,  int_eqEquality,  intEquality,  dependent_functionElimination,  isect_memberEquality,  voidElimination,  voidEquality,  sqequalRule,  independent_pairFormation,  sqequalAxiom,  equalityTransitivity,  equalitySymmetry,  unionElimination,  because_Cache,  universeEquality,  applyEquality,  imageElimination,  productElimination,  imageMemberEquality,  baseClosed,  instantiate,  equalityElimination,  addEquality,  promote_hyp,  cumulativity,  hypothesis_subsumption

Latex:
\mforall{}[T:Type].  \mforall{}[m:\mBbbN{}].  \mforall{}[L:T  List].    nth\_tl(m;L)  \msim{}  [L[m]  /  nth\_tl(1  +  m;L)]  supposing  m  <  ||L||



Date html generated: 2018_05_21-PM-00_32_41
Last ObjectModification: 2018_05_19-AM-06_42_44

Theory : list_1


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