Nuprl Lemma : geo-add-length-between-iff
∀e:BasicGeometry. ∀[a,b,c:Point].  uiff(B(abc);|ac| = |ab| + |bc| ∈ Length)
Proof
Definitions occuring in Statement : 
geo-add-length: p + q, 
geo-length: |s|, 
geo-length-type: Length, 
geo-mk-seg: ab, 
basic-geometry: BasicGeometry, 
geo-between: B(abc), 
geo-point: Point, 
uiff: uiff(P;Q), 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
uimplies: b supposing a, 
subtype_rel: A ⊆r B, 
guard: {T}, 
prop: ℙ, 
geo-between: B(abc), 
not: ¬A, 
implies: P ⇒ Q, 
false: False, 
basic-geometry: BasicGeometry, 
euclidean-plane: EuclideanPlane, 
or: P ∨ Q, 
stable: Stable{P}, 
geo-eq: a ≡ b, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
exists: ∃x:A. B[x], 
geo-strict-between: a-b-c, 
cand: A c∧ B, 
squash: ↓T, 
true: True
Latex:
\mforall{}e:BasicGeometry.  \mforall{}[a,b,c:Point].    uiff(B(abc);|ac|  =  |ab|  +  |bc|)
Date html generated:
2020_05_20-AM-09_53_44
Last ObjectModification:
2020_01_13-PM-03_24_05
Theory : euclidean!plane!geometry
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