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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