Nuprl Lemma : bdd-diff-iff-eventual

∀f,g:ℕ+ ⟶ ℤ.  (∃m:ℕ+. ∃B:ℕ. ∀n:{m...}. (|(f n) - g n| ≤ B) ⇐⇒ bdd-diff(f;g))


Proof




Definitions occuring in Statement :  bdd-diff: bdd-diff(f;g),  absval: |i|,  int_upper: {i...},  nat_plus: ℕ+,  nat: ℕ,  le: A ≤ B,  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  iff: P ⇐⇒ Q,  apply: f a,  function: x:A ⟶ B[x],  subtract: n - m,  int: ℤ
Definitions unfolded in proof :  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  and: P ∧ Q,  implies: P ⇒ Q,  member: t ∈ T,  prop: ℙ,  uall: ∀[x:A]. B[x],  so_lambda: λ2x.t[x],  nat_plus: ℕ+,  int_upper: {i...},  nat: ℕ,  le: A ≤ B,  guard: {T},  uimplies: b supposing a,  subtype_rel: A ⊆r B,  so_apply: x[s],  rev_implies: P ⇐ Q,  exists: ∃x:A. B[x],  decidable: Dec(P),  or: P ∨ Q,  sq_type: SQType(T),  bdd-diff: bdd-diff(f;g),  ge: i ≥ j ,  satisfiable_int_formula: satisfiable_int_formula(fmla),  false: False,  not: ¬A,  top: Top,  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  uiff: uiff(P;Q),  ifthenelse: if b then t else f fi ,  bfalse: ff,  bnot: ¬bb,  assert: ↑b,  cand: A c∧ B,  less_than': less_than'(a;b),  true: True,  less_than: a < b,  squash: ↓T
Lemmas referenced :  exists_wf,  nat_plus_wf,  nat_wf,  all_wf,  int_upper_wf,  le_wf,  absval_wf,  subtract_wf,  less_than_transitivity1,  less_than_wf,  bdd-diff_wf,  decidable__equal_int,  subtype_base_sq,  int_subtype_base,  subtype_rel_sets,  nat_plus_properties,  nat_properties,  decidable__le,  satisfiable-full-omega-tt,  intformand_wf,  intformnot_wf,  intformle_wf,  itermVar_wf,  intformless_wf,  itermConstant_wf,  intformeq_wf,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_le_lemma,  int_term_value_var_lemma,  int_formula_prop_less_lemma,  int_term_value_constant_lemma,  int_formula_prop_eq_lemma,  int_formula_prop_wf,  imax_wf,  imax-list_wf,  map-length,  length-from-upto,  lt_int_wf,  bool_wf,  eqtt_to_assert,  assert_of_lt_int,  decidable__lt,  itermSubtract_wf,  int_term_value_subtract_lemma,  eqff_to_assert,  equal_wf,  bool_cases_sqequal,  bool_subtype_base,  assert-bnot,  imax_ub,  imax-list-ub,  map_wf,  false_wf,  not-lt-2,  add_functionality_wrt_le,  add-commutes,  zero-add,  le-add-cancel,  from-upto_wf,  l_exists_iff,  l_member_wf,  member-map,  member-from-upto
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  independent_pairFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesis,  sqequalRule,  lambdaEquality,  setElimination,  rename,  because_Cache,  applyEquality,  functionExtensionality,  hypothesisEquality,  dependent_set_memberEquality,  productElimination,  natural_numberEquality,  independent_isectElimination,  functionEquality,  intEquality,  dependent_functionElimination,  unionElimination,  instantiate,  cumulativity,  independent_functionElimination,  dependent_pairFormation,  setEquality,  applyLambdaEquality,  int_eqEquality,  isect_memberEquality,  voidElimination,  voidEquality,  computeAll,  equalityElimination,  equalityTransitivity,  equalitySymmetry,  promote_hyp,  inlFormation,  inrFormation,  productEquality,  imageMemberEquality,  baseClosed

Latex:
\mforall{}f,g:\mBbbN{}\msupplus{}  {}\mrightarrow{}  \mBbbZ{}.    (\mexists{}m:\mBbbN{}\msupplus{}.  \mexists{}B:\mBbbN{}.  \mforall{}n:\{m...\}.  (|(f  n)  -  g  n|  \mleq{}  B)  \mLeftarrow{}{}\mRightarrow{}  bdd-diff(f;g))



Date html generated: 2017_10_02-PM-07_13_04
Last ObjectModification: 2017_07_28-AM-07_20_00

Theory : reals


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