Nuprl Lemma : cross-product-equal-0-iff

∀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|)) ∨ (∀l:ℕ3 ⟶ |r|. ((a . l) = 0 ∈ |r| ⇐⇒ (b . l) = 0 ∈ |r|))))


Proof




Definitions occuring in Statement :  scalar-product: (a . b),  cross-product: (a x b),  zero-vector: 0,  int_seg: {i..j-},  decidable: Dec(P),  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  implies: P ⇒ Q,  or: P ∨ Q,  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 :  so_apply: x[s],  not: ¬A,  false: False,  less_than': less_than'(a;b),  le: A ≤ B,  nat: ℕ,  so_lambda: λ2x.t[x],  rev_implies: P ⇐ Q,  rng: Rng,  crng: CRng,  integ_dom: IntegDom{i},  uall: ∀[x:A]. B[x],  prop: ℙ,  member: t ∈ T,  and: P ∧ Q,  iff: P ⇐⇒ Q,  implies: P ⇒ Q,  all: ∀x:A. B[x],  guard: {T},  or: P ∨ Q,  uimplies: b supposing a,  subtype_rel: A ⊆r B,  infix_ap: x f y,  squash: ↓T,  true: True,  exists: ∃x:A. B[x],  integ_dom_p: IsIntegDom(r),  decidable: Dec(P),  sq_exists: ∃x:A [B[x]]
Lemmas referenced :  integ_dom_wf,  decidable_wf,  rng_zero_wf,  le_wf,  false_wf,  scalar-product_wf,  iff_wf,  all_wf,  or_wf,  zero-vector_wf,  cross-product_wf,  rng_car_wf,  int_seg_wf,  equal_wf,  cross-product-equal-0,  rng_times_zero,  iff_weakening_equal,  rng_times_wf,  squash_wf,  true_wf,  scalar-product-mul,  crng_times_comm,  cross-product-0,  not_wf,  cross-product-non-zero-implies-ext,  compact-finite,  decidable__equal_compact_domain,  rng_sig_wf,  mul-zero-vector,  rng_one_wf,  rng_minus_wf,  cross-product-anti-comm,  vector-mul_wf
Rules used in proof :  dependent_set_memberEquality,  lambdaEquality,  sqequalRule,  because_Cache,  applyEquality,  functionExtensionality,  hypothesisEquality,  rename,  setElimination,  hypothesis,  natural_numberEquality,  functionEquality,  thin,  isectElimination,  sqequalHypSubstitution,  extract_by_obid,  introduction,  cut,  independent_pairFormation,  lambdaFormation,  sqequalReflexivity,  computationStep,  sqequalTransitivity,  sqequalSubstitution,  inrFormation,  equalitySymmetry,  equalityTransitivity,  inlFormation,  unionElimination,  productElimination,  independent_functionElimination,  dependent_functionElimination,  independent_isectElimination,  baseClosed,  imageMemberEquality,  levelHypothesis,  equalityUniverse,  imageElimination,  applyLambdaEquality,  universeEquality,  productEquality,  cumulativity,  voidElimination

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{}  (\mforall{}l:\mBbbN{}3  {}\mrightarrow{}  |r|.  ((a  .  l)  =  0  \mLeftarrow{}{}\mRightarrow{}  (b  .  l)  =  0))))



Date html generated: 2018_05_21-PM-09_44_10
Last ObjectModification: 2018_01_09-PM-02_07_38

Theory : matrices


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