Nuprl Lemma : not-left-collinear
∀g:OrientedPlane. ∀a,b,c:Point.  ((¬a leftof bc) ⇒ (¬a leftof cb) ⇒ (¬((¬B(abc)) ∧ (¬B(bca)) ∧ (¬B(cab)))))
Proof
Definitions occuring in Statement : 
oriented-plane: OrientedPlane, 
geo-between: B(abc), 
geo-left: a leftof bc, 
geo-point: Point, 
all: ∀x:A. B[x], 
not: ¬A, 
implies: P ⇒ Q, 
and: P ∧ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
member: t ∈ T, 
oriented-plane: OrientedPlane, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
implies: P ⇒ Q, 
not: ¬A, 
false: False, 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
prop: ℙ, 
guard: {T}, 
uimplies: b supposing a, 
geo-colinear: Colinear(a;b;c), 
geo-lsep: a # bc, 
or: P ∨ Q, 
euclidean-plane: EuclideanPlane, 
basic-geometry-: BasicGeometry-
Latex:
\mforall{}g:OrientedPlane.  \mforall{}a,b,c:Point.
    ((\mneg{}a  leftof  bc)  {}\mRightarrow{}  (\mneg{}a  leftof  cb)  {}\mRightarrow{}  (\mneg{}((\mneg{}B(abc))  \mwedge{}  (\mneg{}B(bca))  \mwedge{}  (\mneg{}B(cab)))))
Date html generated:
2020_05_20-AM-09_50_05
Last ObjectModification:
2019_12_20-PM-07_37_36
Theory : euclidean!plane!geometry
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