Nuprl Lemma : approx-in-interval_wf

∀l:ℝ. ∀u:{u:ℝ| l ≤ u} . ∀x:{x:ℝ| x ∈ [l, u]} . ∀n:ℕ+.
  (approx-in-interval(l;u;x;n) ∈ {y:ℝ| (y ∈ [l, u]) ∧ (|x - y| ≤ (r(2)/r(n)))} )


Proof




Definitions occuring in Statement :  approx-in-interval: approx-in-interval(l;u;x;n),  rccint: [l, u],  i-member: r ∈ I,  rdiv: (x/y),  rleq: x ≤ y,  rabs: |x|,  rsub: x - y,  int-to-real: r(n),  real: ℝ,  nat_plus: ℕ+,  all: ∀x:A. B[x],  and: P ∧ Q,  member: t ∈ T,  set: {x:A| B[x]} ,  natural_number: $n
Definitions unfolded in proof :  all: ∀x:A. B[x],  member: t ∈ T,  top: Top,  approx-in-interval: approx-in-interval(l;u;x;n),  has-value: (a)↓,  uall: ∀[x:A]. B[x],  uimplies: b supposing a,  real: ℝ,  nat_plus: ℕ+,  decidable: Dec(P),  or: P ∨ Q,  not: ¬A,  implies: P ⇒ Q,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  false: False,  and: P ∧ Q,  prop: ℙ,  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  uiff: uiff(P;Q),  less_than: a < b,  less_than': less_than'(a;b),  true: True,  squash: ↓T,  cand: A c∧ B,  sq_stable: SqStable(P),  rneq: x ≠ y,  guard: {T},  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  bfalse: ff,  sq_type: SQType(T),  bnot: ¬bb,  ifthenelse: if b then t else f fi ,  assert: ↑b,  int_nzero: ℤ-o,  nequal: a ≠ b ∈ T ,  subtype_rel: A ⊆r B,  rev_uimplies: rev_uimplies(P;Q),  req_int_terms: t1 ≡ t2,  rational-upper-approx: above x within 1/n,  rational-approx: (x within 1/n),  so_lambda: λ2x.t[x],  so_apply: x[s],  rless: x < y,  sq_exists: ∃x:A [B[x]],  rge: x ≥ y,  rational-lower-approx: (below x within 1/n),  le: A ≤ B
Lemmas referenced :  member_rccint_lemma,  istype-void,  value-type-has-value,  int-value-type,  lt_int_wf,  nat_plus_properties,  decidable__lt,  full-omega-unsat,  intformand_wf,  intformnot_wf,  intformless_wf,  itermConstant_wf,  itermMultiply_wf,  itermVar_wf,  istype-int,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_less_lemma,  int_term_value_constant_lemma,  int_term_value_mul_lemma,  int_term_value_var_lemma,  int_formula_prop_wf,  istype-less_than,  eqtt_to_assert,  assert_of_lt_int,  istype-top,  rleq_weakening_equal,  sq_stable__rleq,  rleq_wf,  rabs_wf,  rsub_wf,  rdiv_wf,  int-to-real_wf,  rless-int,  rless_wf,  eqff_to_assert,  bool_cases_sqequal,  subtype_base_sq,  bool_wf,  bool_subtype_base,  assert-bnot,  iff_weakening_uiff,  assert_wf,  less_than_wf,  subtract_wf,  int-rdiv_wf,  intformeq_wf,  int_formula_prop_eq_lemma,  int_subtype_base,  nequal_wf,  nat_plus_wf,  i-member_wf,  rccint_wf,  real_wf,  radd-preserves-rleq,  radd_wf,  itermSubtract_wf,  itermAdd_wf,  rleq_functionality,  rabs-of-nonneg,  req_weakening,  req-iff-rsub-is-0,  real_polynomial_null,  real_term_value_sub_lemma,  real_term_value_add_lemma,  real_term_value_var_lemma,  real_term_value_const_lemma,  set-value-type,  mul_preserves_lt,  set_subtype_base,  rless_functionality,  nat_plus_inc_int_nzero,  int-rdiv-req,  rless-int-fractions,  add-is-int-iff,  multiply-is-int-iff,  int_term_value_add_lemma,  false_wf,  rational-approx-property,  rational-upper-approx-property,  rational-upper-approx_wf,  rational-approx_wf,  rabs-difference-bound-rleq,  rleq_functionality_wrt_implies,  rsub_functionality_wrt_rleq,  req-int-fractions,  decidable__equal_int,  req_functionality,  req_transitivity,  radd-rdiv,  rdiv_functionality,  radd-int,  rleq_weakening_rless,  radd_functionality_wrt_rleq,  rabs-difference-symmetry,  subtract-is-int-iff,  int_term_value_subtract_lemma,  rational-lower-approx-property,  rational-lower-approx_wf,  rleq_transitivity,  decidable__le,  intformle_wf,  int_formula_prop_le_lemma,  mul_preserves_le,  nat_plus_subtype_nat,  rleq-int-fractions
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation_alt,  cut,  sqequalRule,  introduction,  extract_by_obid,  sqequalHypSubstitution,  dependent_functionElimination,  thin,  isect_memberEquality_alt,  voidElimination,  hypothesis,  callbyvalueReduce,  isectElimination,  intEquality,  independent_isectElimination,  applyEquality,  setElimination,  rename,  hypothesisEquality,  because_Cache,  multiplyEquality,  natural_numberEquality,  addEquality,  dependent_set_memberEquality_alt,  unionElimination,  approximateComputation,  independent_functionElimination,  dependent_pairFormation_alt,  lambdaEquality_alt,  int_eqEquality,  independent_pairFormation,  universeIsType,  inhabitedIsType,  equalityElimination,  equalityTransitivity,  equalitySymmetry,  productElimination,  lessCases,  isect_memberFormation_alt,  axiomSqEquality,  isectIsTypeImplies,  imageMemberEquality,  baseClosed,  imageElimination,  productIsType,  closedConclusion,  inrFormation_alt,  equalityIstype,  promote_hyp,  instantiate,  cumulativity,  baseApply,  sqequalBase,  setIsType,  applyLambdaEquality,  pointwiseFunctionality

Latex:
\mforall{}l:\mBbbR{}.  \mforall{}u:\{u:\mBbbR{}|  l  \mleq{}  u\}  .  \mforall{}x:\{x:\mBbbR{}|  x  \mmember{}  [l,  u]\}  .  \mforall{}n:\mBbbN{}\msupplus{}.
    (approx-in-interval(l;u;x;n)  \mmember{}  \{y:\mBbbR{}|  (y  \mmember{}  [l,  u])  \mwedge{}  (|x  -  y|  \mleq{}  (r(2)/r(n)))\}  )



Date html generated: 2019_10_30-AM-09_07_32
Last ObjectModification: 2019_10_10-PM-01_11_54

Theory : reals


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