Nuprl Lemma : qsum_product
∀[a,b,c,d:ℤ]. ∀[x:{a..b + 1-} ⟶ ℚ]. ∀[y:{c..d + 1-} ⟶ ℚ].
  ((Σa ≤ i < b. x[i] * Σc ≤ j < d. y[j]) = Σa ≤ i < b. Σc ≤ j < d. x[i] * y[j] ∈ ℚ)
Proof
Definitions occuring in Statement : 
qsum: Σa ≤ j < b. E[j]
, 
qmul: r * s
, 
rationals: ℚ
, 
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
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
squash: ↓T
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
all: ∀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)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
true: True
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
rationals_wf, 
qmul_com, 
qsum_wf, 
int_seg_properties, 
decidable__le, 
full-omega-unsat, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermVar_wf, 
istype-int, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
decidable__lt, 
intformless_wf, 
itermAdd_wf, 
itermConstant_wf, 
int_formula_prop_less_lemma, 
int_term_value_add_lemma, 
int_term_value_constant_lemma, 
istype-le, 
istype-less_than, 
int_seg_wf, 
qmul_wf, 
subtype_rel_self, 
iff_weakening_equal, 
qsum-linearity1
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
applyEquality, 
thin, 
lambdaEquality_alt, 
sqequalHypSubstitution, 
imageElimination, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
universeIsType, 
instantiate, 
universeEquality, 
sqequalRule, 
dependent_set_memberEquality_alt, 
setElimination, 
rename, 
productElimination, 
independent_pairFormation, 
dependent_functionElimination, 
unionElimination, 
natural_numberEquality, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation_alt, 
int_eqEquality, 
Error :memTop, 
voidElimination, 
addEquality, 
productIsType, 
because_Cache, 
imageMemberEquality, 
baseClosed, 
functionIsType, 
isect_memberEquality_alt, 
axiomEquality, 
isectIsTypeImplies, 
inhabitedIsType
Latex:
\mforall{}[a,b,c,d:\mBbbZ{}].  \mforall{}[x:\{a..b  +  1\msupminus{}\}  {}\mrightarrow{}  \mBbbQ{}].  \mforall{}[y:\{c..d  +  1\msupminus{}\}  {}\mrightarrow{}  \mBbbQ{}].
    ((\mSigma{}a  \mleq{}  i  <  b.  x[i]  *  \mSigma{}c  \mleq{}  j  <  d.  y[j])  =  \mSigma{}a  \mleq{}  i  <  b.  \mSigma{}c  \mleq{}  j  <  d.  x[i]  *  y[j])
Date html generated:
2020_05_20-AM-09_26_05
Last ObjectModification:
2019_12_31-PM-04_59_40
Theory : rationals
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