Nuprl Lemma : Dbet-to-between
∀e:EuclideanPlane. ∀a,b,c:Point.  ((∀A,B,C:Point.  (A # BC 
⇒ |AC| < |AB| + |BC|)) 
⇒ Dbet(e;a;b;c) 
⇒ B(abc))
Proof
Definitions occuring in Statement : 
dist-bet: Dbet(g;a;b;c)
, 
geo-lt: p < q
, 
geo-add-length: p + q
, 
geo-length: |s|
, 
geo-mk-seg: ab
, 
euclidean-plane: EuclideanPlane
, 
geo-between: B(abc)
, 
geo-lsep: a # bc
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
uimplies: b supposing a
, 
basic-geometry: BasicGeometry
, 
euclidean-plane: EuclideanPlane
, 
or: P ∨ Q
, 
not: ¬A
, 
false: False
, 
stable: Stable{P}
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
basic-geometry-: BasicGeometry-
, 
rev_implies: P 
⇐ Q
, 
geo-strict-between: a-b-c
, 
uiff: uiff(P;Q)
, 
squash: ↓T
, 
true: True
Latex:
\mforall{}e:EuclideanPlane.  \mforall{}a,b,c:Point.
    ((\mforall{}A,B,C:Point.    (A  \#  BC  {}\mRightarrow{}  |AC|  <  |AB|  +  |BC|))  {}\mRightarrow{}  Dbet(e;a;b;c)  {}\mRightarrow{}  B(abc))
Date html generated:
2020_05_20-AM-10_48_52
Last ObjectModification:
2020_01_13-PM-06_50_12
Theory : euclidean!plane!geometry
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