Nuprl Lemma : exists-rneq-iff
∀n:ℕ. ∀a,b:ℕn ⟶ ℝ.  (∃i:ℕn. a[i] ≠ b[i] 
⇐⇒ r0 < Σ{|a[i] - b[i]| | 0≤i≤n - 1})
Proof
Definitions occuring in Statement : 
rsum: Σ{x[k] | n≤k≤m}
, 
rneq: x ≠ y
, 
rless: x < y
, 
rabs: |x|
, 
rsub: x - y
, 
int-to-real: r(n)
, 
real: ℝ
, 
int_seg: {i..j-}
, 
nat: ℕ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
function: x:A ⟶ B[x]
, 
subtract: n - m
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
nat: ℕ
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
ge: i ≥ j 
, 
exists: ∃x:A. B[x]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
uimplies: b supposing a
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
false: False
, 
top: Top
, 
prop: ℙ
, 
le: A ≤ B
, 
less_than: a < b
, 
rev_implies: P 
⇐ Q
, 
rless: x < y
, 
sq_exists: ∃x:{A| B[x]}
, 
nat_plus: ℕ+
Lemmas referenced : 
subtract-add-cancel, 
rsum-of-nonneg-positive-iff, 
subtract_wf, 
rabs_wf, 
rsub_wf, 
int_seg_wf, 
nat_properties, 
decidable__lt, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformless_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
lelt_wf, 
zero-rleq-rabs, 
nat_plus_properties, 
rless_wf, 
int-to-real_wf, 
rsum_wf, 
iff_wf, 
exists_wf, 
rneq_wf, 
real_wf, 
nat_wf, 
rneq-iff-rabs, 
rneq-if-rabs
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
setElimination, 
rename, 
hypothesisEquality, 
hypothesis, 
natural_numberEquality, 
addLevel, 
productElimination, 
independent_pairFormation, 
impliesFunctionality, 
dependent_functionElimination, 
because_Cache, 
sqequalRule, 
lambdaEquality, 
applyEquality, 
functionExtensionality, 
dependent_set_memberEquality, 
unionElimination, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
addEquality, 
functionEquality
Latex:
\mforall{}n:\mBbbN{}.  \mforall{}a,b:\mBbbN{}n  {}\mrightarrow{}  \mBbbR{}.    (\mexists{}i:\mBbbN{}n.  a[i]  \mneq{}  b[i]  \mLeftarrow{}{}\mRightarrow{}  r0  <  \mSigma{}\{|a[i]  -  b[i]|  |  0\mleq{}i\mleq{}n  -  1\})
Date html generated:
2017_10_03-AM-09_00_31
Last ObjectModification:
2017_06_16-AM-11_47_25
Theory : reals
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