Nuprl Lemma : function-diff-small-or-interval-proper

∀I:Interval. ∀f:I ⟶ℝ. ∀x,y:{x:ℝ| x ∈ I} . ∀e:{e:ℝ| r0 < e} .
  (f[x] continuous for x ∈ I ⇒ ((|f[x] - f[y]| ≤ e) ∨ (r0 < |x - y|)))


Proof




Definitions occuring in Statement :  continuous: f[x] continuous for x ∈ I,  rfun: I ⟶ℝ,  i-member: r ∈ I,  interval: Interval,  rleq: x ≤ y,  rless: x < y,  rabs: |x|,  rsub: x - y,  int-to-real: r(n),  real: ℝ,  so_apply: x[s],  all: ∀x:A. B[x],  implies: P ⇒ Q,  or: P ∨ Q,  set: {x:A| B[x]} ,  natural_number: $n
Definitions unfolded in proof :  all: ∀x:A. B[x],  implies: P ⇒ Q,  member: t ∈ T,  sq_stable: SqStable(P),  squash: ↓T,  uall: ∀[x:A]. B[x],  so_lambda: λ2x.t[x],  rfun: I ⟶ℝ,  so_apply: x[s],  prop: ℙ,  continuous: f[x] continuous for x ∈ I,  i-approx: i-approx(I;n),  rccint: [l, u],  nat_plus: ℕ+,  less_than: a < b,  less_than': less_than'(a;b),  true: True,  and: P ∧ Q,  iff: P ⇐⇒ Q,  top: Top,  exists: ∃x:A. B[x],  sq_exists: ∃x:{A| B[x]},  subinterval: I ⊆ J ,  cand: A c∧ B,  uimplies: b supposing a,  rneq: x ≠ y,  guard: {T},  or: P ∨ Q,  rev_implies: P ⇐ Q,  rless: x < y,  decidable: Dec(P),  satisfiable_int_formula: satisfiable_int_formula(fmla),  false: False,  not: ¬A,  rleq: x ≤ y,  rnonneg: rnonneg(x),  le: A ≤ B,  subtype_rel: A ⊆r B,  label: ...$L... t
Lemmas referenced :  rmin-rmax-subinterval,  sq_stable__i-member,  continuous_functionality_wrt_subinterval,  i-member_wf,  real_wf,  rccint_wf,  rmin_wf,  rmax_wf,  less_than_wf,  rccint-icompact,  rmin-rleq-rmax,  icompact_wf,  member_rccint_lemma,  small-reciprocal-real,  sq_stable__and,  rless_wf,  int-to-real_wf,  all_wf,  rleq_wf,  rabs_wf,  rsub_wf,  rdiv_wf,  rless-int,  nat_plus_properties,  decidable__lt,  satisfiable-full-omega-tt,  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,  sq_stable__rless,  sq_stable__all,  sq_stable__rleq,  less_than'_wf,  nat_plus_wf,  squash_wf,  continuous_wf,  set_wf,  rfun_wf,  interval_wf,  rless-cases,  rmin-rleq,  rleq-rmax,  rleq_weakening_rless,  rless_transitivity2
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  dependent_functionElimination,  thin,  hypothesisEquality,  setElimination,  rename,  hypothesis,  independent_functionElimination,  sqequalRule,  imageMemberEquality,  baseClosed,  imageElimination,  because_Cache,  isectElimination,  lambdaEquality,  applyEquality,  dependent_set_memberEquality,  setEquality,  natural_numberEquality,  independent_pairFormation,  productElimination,  isect_memberEquality,  voidElimination,  voidEquality,  functionEquality,  productEquality,  independent_isectElimination,  inrFormation,  unionElimination,  dependent_pairFormation,  int_eqEquality,  intEquality,  computeAll,  independent_pairEquality,  minusEquality,  axiomEquality,  equalityTransitivity,  equalitySymmetry,  inlFormation

Latex:
\mforall{}I:Interval.  \mforall{}f:I  {}\mrightarrow{}\mBbbR{}.  \mforall{}x,y:\{x:\mBbbR{}|  x  \mmember{}  I\}  .  \mforall{}e:\{e:\mBbbR{}|  r0  <  e\}  .
    (f[x]  continuous  for  x  \mmember{}  I  {}\mRightarrow{}  ((|f[x]  -  f[y]|  \mleq{}  e)  \mvee{}  (r0  <  |x  -  y|)))



Date html generated: 2016_10_26-AM-09_55_54
Last ObjectModification: 2016_08_29-PM-10_09_17

Theory : reals


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