Nuprl Lemma : rsum-triangle-inequality2
∀[n,m:ℤ]. ∀[x,y:{n..m + 1-} ⟶ ℝ].  ((Σ{|y[i]| | n≤i≤m} - Σ{|x[i]| | n≤i≤m}) ≤ Σ{|x[i] + y[i]| | n≤i≤m})
Proof
Definitions occuring in Statement : 
rsum: Σ{x[k] | n≤k≤m}
, 
rleq: x ≤ y
, 
rabs: |x|
, 
rsub: x - y
, 
radd: a + b
, 
real: ℝ
, 
int_seg: {i..j-}
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
function: x:A ⟶ B[x]
, 
add: n + m
, 
natural_number: $n
, 
int: ℤ
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
rleq: x ≤ y
, 
rnonneg: rnonneg(x)
, 
all: ∀x:A. B[x]
, 
le: A ≤ B
, 
and: P ∧ Q
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
false: False
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
subtype_rel: A ⊆r B
, 
prop: ℙ
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
top: Top
, 
rev_uimplies: rev_uimplies(P;Q)
, 
rge: x ≥ y
, 
guard: {T}
, 
uiff: uiff(P;Q)
Lemmas referenced : 
req_weakening, 
radd_comm, 
rabs_functionality, 
rsum_functionality2, 
rleq_functionality, 
rsum-triangle-inequality1, 
rleq_functionality_wrt_implies, 
rleq_weakening_equal, 
le_wf, 
lelt_wf, 
int_formula_prop_wf, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_add_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_and_lemma, 
intformle_wf, 
itermConstant_wf, 
itermAdd_wf, 
itermVar_wf, 
intformless_wf, 
intformnot_wf, 
intformand_wf, 
satisfiable-full-omega-tt, 
decidable__lt, 
real_wf, 
nat_plus_wf, 
int_seg_wf, 
radd_wf, 
rabs_wf, 
rsum_wf, 
rsub_wf, 
less_than'_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalRule, 
sqequalHypSubstitution, 
lambdaEquality, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
productElimination, 
independent_pairEquality, 
because_Cache, 
lemma_by_obid, 
isectElimination, 
applyEquality, 
hypothesis, 
addEquality, 
natural_numberEquality, 
minusEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
functionEquality, 
isect_memberEquality, 
intEquality, 
voidElimination, 
dependent_set_memberEquality, 
independent_pairFormation, 
unionElimination, 
independent_isectElimination, 
dependent_pairFormation, 
int_eqEquality, 
voidEquality, 
computeAll, 
lambdaFormation
Latex:
\mforall{}[n,m:\mBbbZ{}].  \mforall{}[x,y:\{n..m  +  1\msupminus{}\}  {}\mrightarrow{}  \mBbbR{}].
    ((\mSigma{}\{|y[i]|  |  n\mleq{}i\mleq{}m\}  -  \mSigma{}\{|x[i]|  |  n\mleq{}i\mleq{}m\})  \mleq{}  \mSigma{}\{|x[i]  +  y[i]|  |  n\mleq{}i\mleq{}m\})
Date html generated:
2016_05_18-AM-07_48_30
Last ObjectModification:
2016_01_17-AM-02_08_57
Theory : reals
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