Nuprl Lemma : rabs-rlog-difference-bound
∀x,y:ℝ.  ((r0 < x) 
⇒ (r0 < y) 
⇒ (|rlog(y) - rlog(x)| ≤ (|y - x|/rmin(x;y))))
Proof
Definitions occuring in Statement : 
rlog: rlog(x)
, 
rdiv: (x/y)
, 
rleq: x ≤ y
, 
rless: x < y
, 
rabs: |x|
, 
rmin: rmin(x;y)
, 
rsub: x - y
, 
int-to-real: r(n)
, 
real: ℝ
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
cand: A c∧ B
, 
uall: ∀[x:A]. B[x]
, 
iproper: iproper(I)
, 
i-finite: i-finite(I)
, 
rciint: [l, ∞)
, 
isl: isl(x)
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
bfalse: ff
, 
false: False
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
uimplies: b supposing a
, 
rneq: x ≠ y
, 
guard: {T}
, 
or: P ∨ Q
, 
rfun: I ⟶ℝ
, 
top: Top
, 
sq_stable: SqStable(P)
, 
uiff: uiff(P;Q)
, 
rev_uimplies: rev_uimplies(P;Q)
, 
squash: ↓T
, 
subinterval: I ⊆ J 
, 
rev_implies: P 
⇐ Q
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
not: ¬A
, 
rge: x ≥ y
Lemmas referenced : 
rmin_strict_ub, 
mean-value-for-bounded-derivative, 
rciint_wf, 
rmin_wf, 
true_wf, 
false_wf, 
rdiv_wf, 
int-to-real_wf, 
rless_wf, 
real_wf, 
rlog_wf, 
member_rciint_lemma, 
rless_transitivity1, 
i-member_wf, 
rleq_wf, 
sq_stable__req, 
req_functionality, 
rdiv_functionality, 
req_weakening, 
req_wf, 
set_wf, 
derivative-rlog, 
member_roiint_lemma, 
derivative_functionality_wrt_subinterval, 
roiint_wf, 
sq_stable__rless, 
sq_stable__rleq, 
rabs_wf, 
rmul_preserves_rleq, 
rmul_wf, 
rleq-int, 
rleq_functionality, 
rabs-of-nonneg, 
uiff_transitivity, 
rmul-rdiv-cancel2, 
rmul-zero-both, 
req_inversion, 
rmul-assoc, 
rmul_functionality, 
rmul_comm, 
rmul-ac, 
rmul-rdiv-cancel, 
rmul-one-both, 
rsub_wf, 
rmin-rleq, 
equal_wf, 
rleq_functionality_wrt_implies, 
rleq_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
because_Cache, 
productElimination, 
independent_functionElimination, 
hypothesis, 
independent_pairFormation, 
isectElimination, 
sqequalRule, 
voidElimination, 
productEquality, 
natural_numberEquality, 
independent_isectElimination, 
inrFormation, 
lambdaEquality, 
setElimination, 
rename, 
isect_memberEquality, 
voidEquality, 
dependent_set_memberEquality, 
setEquality, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}x,y:\mBbbR{}.    ((r0  <  x)  {}\mRightarrow{}  (r0  <  y)  {}\mRightarrow{}  (|rlog(y)  -  rlog(x)|  \mleq{}  (|y  -  x|/rmin(x;y))))
Date html generated:
2017_10_04-PM-10_26_09
Last ObjectModification:
2017_07_28-AM-08_49_54
Theory : reals_2
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