Nuprl Lemma : geo-not-triangle
∀e:HeytingGeometry. ∀a,b,c:Point.  ((¬a # bc) ⇒ (¬((¬B(abc)) ∧ (¬B(bca)) ∧ (¬B(cab)))))
Proof
Definitions occuring in Statement : 
geo-triangle: a # bc, 
heyting-geometry: HeytingGeometry, 
geo-between: B(abc), 
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], 
implies: P ⇒ Q, 
not: ¬A, 
false: False, 
member: t ∈ T, 
heyting-geometry: HeytingGeometry, 
geo-colinear: Colinear(a;b;c), 
geo-lsep: a # bc, 
or: P ∨ Q, 
geo-triangle: a # bc, 
and: P ∧ Q, 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
guard: {T}, 
uimplies: b supposing a, 
prop: ℙ, 
stable: Stable{P}
Latex:
\mforall{}e:HeytingGeometry.  \mforall{}a,b,c:Point.    ((\mneg{}a  \#  bc)  {}\mRightarrow{}  (\mneg{}((\mneg{}B(abc))  \mwedge{}  (\mneg{}B(bca))  \mwedge{}  (\mneg{}B(cab)))))
Date html generated:
2020_05_20-AM-10_32_39
Last ObjectModification:
2019_12_28-AM-08_24_20
Theory : euclidean!plane!geometry
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