Nuprl Lemma : req-iff-rabs-rleq-bound

∀x,y:ℝ.  (x = y ⇐⇒ ∃B:ℕ+. ∀m:ℕ+. (|x - y| ≤ (r(B)/r(m))))


Proof




Definitions occuring in Statement :  rdiv: (x/y),  rleq: x ≤ y,  rabs: |x|,  rsub: x - y,  req: x = y,  int-to-real: r(n),  real: ℝ,  nat_plus: ℕ+,  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  iff: P ⇐⇒ Q
Definitions unfolded in proof :  all: ∀x:A. B[x],  member: t ∈ T,  iff: P ⇐⇒ Q,  and: P ∧ Q,  implies: P ⇒ Q,  prop: ℙ,  uall: ∀[x:A]. B[x],  rev_implies: P ⇐ Q,  so_lambda: λ2x.t[x],  nat_plus: ℕ+,  uimplies: b supposing a,  rneq: x ≠ y,  guard: {T},  or: P ∨ Q,  decidable: Dec(P),  not: ¬A,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  false: False,  top: Top,  so_apply: x[s],  less_than: a < b,  squash: ↓T,  less_than': less_than'(a;b),  true: True,  uiff: uiff(P;Q),  rev_uimplies: rev_uimplies(P;Q),  rge: x ≥ y
Lemmas referenced :  req-iff-rabs-rleq,  req_wf,  nat_plus_wf,  exists_wf,  all_wf,  rleq_wf,  rabs_wf,  rsub_wf,  rdiv_wf,  int-to-real_wf,  rless-int,  nat_plus_properties,  decidable__lt,  full-omega-unsat,  intformand_wf,  intformnot_wf,  intformless_wf,  itermConstant_wf,  itermVar_wf,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_less_lemma,  int_term_value_constant_lemma,  int_term_value_var_lemma,  int_formula_prop_wf,  rless_wf,  real_wf,  less_than_wf,  mul_nat_plus,  mul_bounds_1b,  rleq-int-fractions,  decidable__le,  intformle_wf,  itermMultiply_wf,  int_formula_prop_le_lemma,  int_term_value_mul_lemma,  rleq_functionality_wrt_implies,  rleq_weakening_equal
Rules used in proof :  cut,  introduction,  extract_by_obid,  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  hypothesis,  sqequalHypSubstitution,  dependent_functionElimination,  thin,  hypothesisEquality,  independent_pairFormation,  productElimination,  independent_functionElimination,  isectElimination,  sqequalRule,  lambdaEquality,  because_Cache,  setElimination,  rename,  independent_isectElimination,  inrFormation,  natural_numberEquality,  unionElimination,  approximateComputation,  dependent_pairFormation,  int_eqEquality,  intEquality,  isect_memberEquality,  voidElimination,  voidEquality,  dependent_set_memberEquality,  imageMemberEquality,  baseClosed,  multiplyEquality,  equalityTransitivity,  equalitySymmetry

Latex:
\mforall{}x,y:\mBbbR{}.    (x  =  y  \mLeftarrow{}{}\mRightarrow{}  \mexists{}B:\mBbbN{}\msupplus{}.  \mforall{}m:\mBbbN{}\msupplus{}.  (|x  -  y|  \mleq{}  (r(B)/r(m))))



Date html generated: 2018_05_22-PM-01_57_53
Last ObjectModification: 2017_10_26-PM-02_20_36

Theory : reals


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