Nuprl Lemma : cross-product-non-zero-implies-ext
∀r:IntegDom{i}
  ((∀x,y:|r|.  Dec(x = y ∈ |r|))
  
⇒ (∀a:{a:ℕ3 ⟶ |r|| ¬(a = 0 ∈ (ℕ3 ⟶ |r|))} . ∀b:{b:ℕ3 ⟶ |r|| 
                                                    (¬(b = 0 ∈ (ℕ3 ⟶ |r|))) ∧ (¬((a x b) = 0 ∈ (ℕ3 ⟶ |r|)))} .
        (∃l:{p:ℕ3 ⟶ |r|| ¬(p = 0 ∈ (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]
, 
sq_exists: ∃x:A [B[x]]
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
, 
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 : 
member: t ∈ T
, 
bfalse: ff
, 
it: ⋅
, 
mk_deq: mk_deq(p)
, 
isl: isl(x)
, 
btrue: tt
, 
vector-mul: (c*a)
, 
infix_ap: x f y
, 
eq_int: (i =z j)
, 
ifthenelse: if b then t else f fi 
, 
nonzero-cross-imp: nonzero-cross-imp(r;eq;a;b)
, 
cross-product-non-zero-implies, 
sq_stable__and, 
sq_stable__not, 
decidable__exists_int_seg, 
decidable__cand, 
decidable__not, 
decidable__equal_compact_domain, 
compact-finite, 
any: any x
, 
decidable__and2, 
decidable__implies, 
decidable__false, 
deq-exists, 
decidable__equal_bool, 
decidable__and, 
btrue_neq_bfalse, 
uall: ∀[x:A]. B[x]
, 
so_lambda: so_lambda4, 
so_apply: x[s1;s2;s3;s4]
, 
so_lambda: λ2x.t[x]
, 
top: Top
, 
so_apply: x[s]
, 
uimplies: b supposing a
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
has-value: (a)↓
Lemmas referenced : 
cross-product-non-zero-implies, 
lifting-strict-decide, 
istype-void, 
strict4-decide, 
lifting-strict-int_eq, 
strict4-spread, 
has-value_wf_base, 
is-exception_wf, 
sq_stable__and, 
sq_stable__not, 
decidable__exists_int_seg, 
decidable__cand, 
decidable__not, 
decidable__equal_compact_domain, 
compact-finite, 
decidable__and2, 
decidable__implies, 
decidable__false, 
deq-exists, 
decidable__equal_bool, 
decidable__and, 
btrue_neq_bfalse
Rules used in proof : 
introduction, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
cut, 
instantiate, 
extract_by_obid, 
hypothesis, 
sqequalRule, 
thin, 
sqequalHypSubstitution, 
equalityTransitivity, 
equalitySymmetry, 
isectElimination, 
baseClosed, 
isect_memberEquality_alt, 
voidElimination, 
independent_isectElimination, 
inhabitedIsType, 
lambdaFormation_alt, 
sqequalSqle, 
divergentSqle, 
callbyvalueSpread, 
productElimination, 
sqleReflexivity, 
equalityIstype, 
hypothesisEquality, 
dependent_functionElimination, 
independent_functionElimination, 
spreadExceptionCases, 
axiomSqleEquality, 
exceptionSqequal, 
baseApply, 
closedConclusion
Latex:
\mforall{}r:IntegDom\{i\}
    ((\mforall{}x,y:|r|.    Dec(x  =  y))
    {}\mRightarrow{}  (\mforall{}a:\{a:\mBbbN{}3  {}\mrightarrow{}  |r||  \mneg{}(a  =  0)\}  .  \mforall{}b:\{b:\mBbbN{}3  {}\mrightarrow{}  |r||  (\mneg{}(b  =  0))  \mwedge{}  (\mneg{}((a  x  b)  =  0))\}  .
                (\mexists{}l:\{p:\mBbbN{}3  {}\mrightarrow{}  |r||  \mneg{}(p  =  0)\}    [(((a  .  l)  =  0)  \mwedge{}  (\mneg{}((b  .  l)  =  0)))])))
Date html generated:
2020_05_20-AM-09_03_58
Last ObjectModification:
2020_01_10-PM-02_17_37
Theory : matrices
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