Nuprl Lemma : ratio-test-ext
∀x:ℕ ⟶ ℝ. ∀N:ℕ.
  ((∀c:{c:ℝ| (r0 ≤ c) ∧ (c < r1)} . ((∀n:{N...}. (|x[n + 1]| ≤ (c * |x[n]|))) 
⇒ Σn.x[n]↓))
  ∧ (∀c:{c:ℝ| r1 < c} . ((∀n:{N...}. ((c * |x[n]|) < |x[n + 1]|)) 
⇒ Σn.x[n]↑)))
Proof
Definitions occuring in Statement : 
series-diverges: Σn.x[n]↑
, 
series-converges: Σn.x[n]↓
, 
rleq: x ≤ y
, 
rless: x < y
, 
rabs: |x|
, 
rmul: a * b
, 
int-to-real: r(n)
, 
real: ℝ
, 
int_upper: {i...}
, 
nat: ℕ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
, 
function: x:A ⟶ B[x]
, 
add: n + m
, 
natural_number: $n
Definitions unfolded in proof : 
member: t ∈ T
, 
so_apply: x[s]
, 
rabs: |x|
, 
subtract: n - m
, 
ratio-test, 
comparison-test-ext, 
series-converges-tail2-ext, 
series-converges-rmul-ext, 
geometric-series-converges-ext, 
series-diverges-trivially, 
rless_transitivity2, 
rless_functionality, 
decidable__le, 
any: any x
, 
rleq_functionality_wrt_implies, 
rless-iff4, 
rless-iff-large-diff, 
rleq_functionality, 
regular-less-iff, 
decidable__and, 
decidable__not, 
decidable__less_than', 
decidable__implies, 
decidable__false, 
uall: ∀[x:A]. B[x]
, 
so_lambda: so_lambda(x,y,z,w.t[x; y; z; w])
, 
so_apply: x[s1;s2;s3;s4]
, 
so_lambda: λ2x.t[x]
, 
top: Top
, 
uimplies: b supposing a
Lemmas referenced : 
ratio-test, 
lifting-strict-decide, 
istype-void, 
strict4-decide, 
lifting-strict-less, 
comparison-test-ext, 
series-converges-tail2-ext, 
series-converges-rmul-ext, 
geometric-series-converges-ext, 
series-diverges-trivially, 
rless_transitivity2, 
rless_functionality, 
decidable__le, 
rleq_functionality_wrt_implies, 
rless-iff4, 
rless-iff-large-diff, 
rleq_functionality, 
regular-less-iff, 
decidable__and, 
decidable__not, 
decidable__less_than', 
decidable__implies, 
decidable__false
Rules used in proof : 
introduction, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
cut, 
instantiate, 
extract_by_obid, 
hypothesis, 
sqequalRule, 
thin, 
sqequalHypSubstitution, 
equalityTransitivity, 
equalitySymmetry, 
isectElimination, 
baseClosed, 
isect_memberEquality_alt, 
voidElimination, 
independent_isectElimination
Latex:
\mforall{}x:\mBbbN{}  {}\mrightarrow{}  \mBbbR{}.  \mforall{}N:\mBbbN{}.
    ((\mforall{}c:\{c:\mBbbR{}|  (r0  \mleq{}  c)  \mwedge{}  (c  <  r1)\}  .  ((\mforall{}n:\{N...\}.  (|x[n  +  1]|  \mleq{}  (c  *  |x[n]|)))  {}\mRightarrow{}  \mSigma{}n.x[n]\mdownarrow{}))
    \mwedge{}  (\mforall{}c:\{c:\mBbbR{}|  r1  <  c\}  .  ((\mforall{}n:\{N...\}.  ((c  *  |x[n]|)  <  |x[n  +  1]|))  {}\mRightarrow{}  \mSigma{}n.x[n]\muparrow{})))
Date html generated:
2019_10_29-AM-10_26_40
Last ObjectModification:
2019_04_02-AM-10_05_04
Theory : reals
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