Nuprl Lemma : cross-product-equal-zero
∀r:IntegDom{i}. ∀a,b:ℕ3 ⟶ |r|.
  ((∀x,y:|r|.  Dec(x = y ∈ |r|))
  ⇒ ((a x b) = 0 ∈ (ℕ3 ⟶ |r|)
     ⇐⇒ (a = 0 ∈ (ℕ3 ⟶ |r|))
         ∨ (b = 0 ∈ (ℕ3 ⟶ |r|))
         ∨ (∃i:ℕ3. ((¬((b i) = 0 ∈ |r|)) ∧ (¬((a i) = 0 ∈ |r|)) ∧ ((b i*a) = (a i*b) ∈ (ℕ3 ⟶ |r|))))))
Proof
Definitions occuring in Statement : 
cross-product: (a x b), 
zero-vector: 0, 
vector-mul: (c*a), 
int_seg: {i..j-}, 
decidable: Dec(P), 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
iff: P ⇐⇒ Q, 
not: ¬A, 
implies: P ⇒ Q, 
or: P ∨ Q, 
and: P ∧ Q, 
apply: f a, 
function: x:A ⟶ B[x], 
natural_number: $n, 
equal: s = t ∈ T, 
integ_dom: IntegDom{i}, 
rng_zero: 0, 
rng_car: |r|
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
member: t ∈ T, 
prop: ℙ, 
uall: ∀[x:A]. B[x], 
integ_dom: IntegDom{i}, 
crng: CRng, 
rng: Rng, 
rev_implies: P ⇐ Q, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
infix_ap: x f y, 
squash: ↓T, 
zero-vector: 0, 
true: True, 
subtype_rel: A ⊆r B, 
uimplies: b supposing a, 
guard: {T}, 
int_seg: {i..j-}, 
lelt: i ≤ j < k, 
le: A ≤ B, 
less_than': less_than'(a;b), 
false: False, 
not: ¬A, 
less_than: a < b, 
cross-product: (a x b), 
select: L[n], 
cons: [a / b], 
subtract: n - m, 
sq_stable: SqStable(P), 
integ_dom_p: IsIntegDom(r), 
decidable: Dec(P), 
or: P ∨ Q, 
sq_type: SQType(T), 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
top: Top, 
cand: A c∧ B, 
vector-mul: (c*a), 
uiff: uiff(P;Q), 
ringeq_int_terms: t1 ≡ t2, 
nequal: a ≠ b ∈ T 
Lemmas referenced : 
equal_wf, 
int_seg_wf, 
rng_car_wf, 
cross-product_wf, 
zero-vector_wf, 
or_wf, 
exists_wf, 
not_wf, 
rng_zero_wf, 
vector-mul_wf, 
all_wf, 
decidable_wf, 
integ_dom_wf, 
rng_plus_wf, 
rng_minus_wf, 
trivial-equal, 
iff_weakening_equal, 
false_wf, 
lelt_wf, 
infix_ap_wf, 
rng_times_wf, 
squash_wf, 
true_wf, 
rng_plus_assoc, 
subtype_rel_self, 
rng_plus_comm, 
rng_plus_inv, 
rng_plus_zero, 
sq_stable__integ_dom_p, 
rng_times_zero, 
decidable__equal_int, 
subtype_base_sq, 
int_subtype_base, 
int_seg_properties, 
int_seg_subtype, 
int_seg_cases, 
full-omega-unsat, 
intformand_wf, 
intformless_wf, 
itermVar_wf, 
itermConstant_wf, 
intformle_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_less_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_le_lemma, 
int_formula_prop_wf, 
crng_times_comm, 
itermAdd_wf, 
itermMultiply_wf, 
itermMinus_wf, 
ringeq-iff-rsub-is-0, 
ring_polynomial_null, 
int-to-ring_wf, 
ring_term_value_add_lemma, 
ring_term_value_mul_lemma, 
ring_term_value_var_lemma, 
ring_term_value_const_lemma, 
int-to-ring-zero, 
ring_term_value_minus_lemma, 
intformnot_wf, 
intformeq_wf, 
int_formula_prop_not_lemma, 
int_formula_prop_eq_lemma, 
cross-product-0, 
rng_sig_wf, 
cross-product-anti-comm, 
rng_one_wf, 
mul-zero-vector, 
cross-product-same, 
cross-product-mul1, 
cross-product-mul2, 
vector-mul-mul
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
independent_pairFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
functionEquality, 
natural_numberEquality, 
hypothesis, 
setElimination, 
rename, 
hypothesisEquality, 
because_Cache, 
sqequalRule, 
lambdaEquality, 
productEquality, 
applyEquality, 
applyLambdaEquality, 
imageElimination, 
imageMemberEquality, 
baseClosed, 
equalityTransitivity, 
equalitySymmetry, 
independent_isectElimination, 
productElimination, 
independent_functionElimination, 
dependent_functionElimination, 
dependent_set_memberEquality, 
functionExtensionality, 
universeEquality, 
instantiate, 
unionElimination, 
hyp_replacement, 
inlFormation, 
cumulativity, 
intEquality, 
hypothesis_subsumption, 
addEquality, 
approximateComputation, 
dependent_pairFormation, 
int_eqEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
inrFormation, 
equalityUniverse, 
levelHypothesis
Latex:
\mforall{}r:IntegDom\{i\}.  \mforall{}a,b:\mBbbN{}3  {}\mrightarrow{}  |r|.
    ((\mforall{}x,y:|r|.    Dec(x  =  y))
    {}\mRightarrow{}  ((a  x  b)  =  0
          \mLeftarrow{}{}\mRightarrow{}  (a  =  0)  \mvee{}  (b  =  0)  \mvee{}  (\mexists{}i:\mBbbN{}3.  ((\mneg{}((b  i)  =  0))  \mwedge{}  (\mneg{}((a  i)  =  0))  \mwedge{}  ((b  i*a)  =  (a  i*b))))))
Date html generated:
2018_05_21-PM-09_41_41
Last ObjectModification:
2018_05_19-PM-04_34_09
Theory : matrices
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