Nuprl Lemma : nth_tl_wf

∀[A:Type]. ∀[as:A List]. ∀[i:ℤ].  (nth_tl(i;as) ∈ A List)


Proof




Definitions occuring in Statement :  nth_tl: nth_tl(n;as),  list: T List,  uall: ∀[x:A]. B[x],  member: t ∈ T,  int: ℤ,  universe: Type
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  all: ∀x:A. B[x],  ge: i ≥ j ,  decidable: Dec(P),  or: P ∨ Q,  subtype_rel: A ⊆r B,  nat: ℕ,  prop: ℙ,  implies: P ⇒ Q,  false: False,  guard: {T},  uimplies: b supposing a,  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,  iff: P ⇐⇒ Q,  and: P ∧ Q,  not: ¬A,  rev_implies: P ⇐ Q,  uiff: uiff(P;Q),  top: Top,  le: A ≤ B,  less_than': less_than'(a;b),  true: True,  bool: 𝔹,  unit: Unit,  it: ⋅,  exists: ∃x:A. B[x],  sq_type: SQType(T),  assert: ↑b
Lemmas referenced :  list_wf,  decidable__le,  nat_wf,  le_wf,  nat_properties,  less_than_transitivity1,  less_than_irreflexivity,  ge_wf,  less_than_wf,  subtract_wf,  false_wf,  not-ge-2,  less-iff-le,  condition-implies-le,  minus-one-mul,  zero-add,  minus-one-mul-top,  minus-add,  minus-minus,  add-associates,  add-swap,  add-commutes,  add_functionality_wrt_le,  add-zero,  le-add-cancel,  le_int_wf,  bool_wf,  eqff_to_assert,  equal_wf,  bool_cases_sqequal,  subtype_base_sq,  bool_subtype_base,  assert-bnot,  assert_of_le_int,  tl_wf,  not-le-2,  minus-zero
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  sqequalHypSubstitution,  hypothesis,  sqequalRule,  axiomEquality,  equalityTransitivity,  equalitySymmetry,  intEquality,  isect_memberEquality,  isectElimination,  thin,  hypothesisEquality,  because_Cache,  extract_by_obid,  cumulativity,  universeEquality,  dependent_functionElimination,  natural_numberEquality,  unionElimination,  hypothesis_subsumption,  lambdaEquality,  setElimination,  rename,  dependent_set_memberEquality,  intWeakElimination,  lambdaFormation,  independent_isectElimination,  independent_functionElimination,  voidElimination,  independent_pairFormation,  productElimination,  addEquality,  applyEquality,  voidEquality,  minusEquality,  equalityElimination,  dependent_pairFormation,  promote_hyp,  instantiate

Latex:
\mforall{}[A:Type].  \mforall{}[as:A  List].  \mforall{}[i:\mBbbZ{}].    (nth\_tl(i;as)  \mmember{}  A  List)



Date html generated: 2017_04_14-AM-08_34_25
Last ObjectModification: 2017_02_27-PM-03_22_08

Theory : list_0


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