Nuprl Lemma : r2-not-left-right
∀a,b,c:ℝ^2.  ((¬r2-left(a;b;c)) 
⇒ (¬r2-left(a;c;b)) 
⇒ (¬((¬rv-T(2;a;b;c)) ∧ (¬rv-T(2;b;c;a)) ∧ (¬rv-T(2;c;a;b)))))
Proof
Definitions occuring in Statement : 
r2-left: r2-left(p;q;r)
, 
rv-T: rv-T(n;a;b;c)
, 
real-vec: ℝ^n
, 
all: ∀x:A. B[x]
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
natural_number: $n
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
false: False
, 
member: t ∈ T
, 
rneq: x ≠ y
, 
or: P ∨ Q
, 
r2-left: r2-left(p;q;r)
, 
rless: x < y
, 
sq_exists: ∃x:{A| B[x]}
, 
prop: ℙ
, 
uall: ∀[x:A]. B[x]
, 
nat: ℕ
, 
le: A ≤ B
, 
and: P ∧ Q
, 
less_than': less_than'(a;b)
, 
uimplies: b supposing a
, 
uiff: uiff(P;Q)
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
req_int_terms: t1 ≡ t2
, 
top: Top
Lemmas referenced : 
r2-det-nonzero, 
rv-pos-angle_wf, 
false_wf, 
le_wf, 
not_wf, 
r2-left_wf, 
real-vec_wf, 
not-rv-pos-angle-implies2, 
int-to-real_wf, 
r2-det_wf, 
rminus_wf, 
rless-implies-rless, 
rsub_wf, 
itermSubtract_wf, 
itermConstant_wf, 
itermVar_wf, 
itermMinus_wf, 
req-iff-rsub-is-0, 
rless_functionality, 
req_weakening, 
r2-det-antisymmetry, 
real_polynomial_null, 
real_term_value_sub_lemma, 
real_term_value_const_lemma, 
real_term_value_var_lemma, 
real_term_value_minus_lemma
Rules used in proof : 
cut, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
thin, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
hypothesisEquality, 
independent_functionElimination, 
hypothesis, 
unionElimination, 
voidElimination, 
because_Cache, 
isectElimination, 
dependent_set_memberEquality, 
natural_numberEquality, 
sqequalRule, 
independent_pairFormation, 
independent_isectElimination, 
productElimination, 
approximateComputation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidEquality
Latex:
\mforall{}a,b,c:\mBbbR{}\^{}2.
    ((\mneg{}r2-left(a;b;c))
    {}\mRightarrow{}  (\mneg{}r2-left(a;c;b))
    {}\mRightarrow{}  (\mneg{}((\mneg{}rv-T(2;a;b;c))  \mwedge{}  (\mneg{}rv-T(2;b;c;a))  \mwedge{}  (\mneg{}rv-T(2;c;a;b)))))
Date html generated:
2017_10_03-AM-11_57_53
Last ObjectModification:
2017_06_14-PM-06_16_11
Theory : reals
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