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

I:Interval. ∀f:I ⟶ℝ. ∀x,y:{x:ℝx ∈ I} . ∀e:{e:ℝr0 < e} .
  (f[x] continuous for x ∈  ((|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: y int-to-real: r(n) real: so_apply: x[s] all: x:A. B[x] implies:  Q or: P ∨ Q set: {x:A| B[x]}  natural_number: $n
Definitions unfolded in proof :  all: x:A. B[x] implies:  Q member: t ∈ T sq_stable: SqStable(P) squash: T uall: [x:A]. B[x] so_lambda: λ2x.t[x] rfun: I ⟶ℝ so_apply: x[s] prop: continuous: f[x] continuous for x ∈ I i-approx: i-approx(I;n) rccint: [l, u] nat_plus: + less_than: a < b less_than': less_than'(a;b) true: True and: P ∧ Q iff: ⇐⇒ Q top: Top exists: x:A. B[x] sq_exists: x:{A| B[x]} subinterval: I ⊆  cand: c∧ B uimplies: supposing a rneq: x ≠ y guard: {T} or: P ∨ Q rev_implies:  Q rless: x < y decidable: Dec(P) satisfiable_int_formula: satisfiable_int_formula(fmla) false: False not: ¬A rleq: x ≤ y rnonneg: rnonneg(x) le: A ≤ B subtype_rel: A ⊆B label: ...$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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