Nuprl Lemma : p5-triangles
∀e:HeytingGeometry. ∀a,b,c:Point.  (a # bc ⇒ ab ≅ cb ⇒ (bac ≅a bca ∧ (∀p,q:Point.  ((b-a-p ∧ b-c-q) ⇒ pac ≅a qca))))
Proof
Definitions occuring in Statement : 
geo-triangle: a # bc, 
heyting-geometry: HeytingGeometry, 
geo-cong-angle: abc ≅a xyz, 
geo-strict-between: a-b-c, 
geo-congruent: ab ≅ cd, 
geo-point: Point, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q, 
cand: A c∧ B, 
geo-cong-angle: abc ≅a xyz, 
member: t ∈ T, 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
guard: {T}, 
uimplies: b supposing a, 
prop: ℙ, 
heyting-geometry: HeytingGeometry, 
uiff: uiff(P;Q), 
exists: ∃x:A. B[x], 
euclidean-plane: EuclideanPlane, 
basic-geometry-: BasicGeometry-, 
squash: ↓T, 
true: True
Latex:
\mforall{}e:HeytingGeometry.  \mforall{}a,b,c:Point.
    (a  \#  bc  {}\mRightarrow{}  ab  \mcong{}  cb  {}\mRightarrow{}  (bac  \mcong{}\msuba{}  bca  \mwedge{}  (\mforall{}p,q:Point.    ((b-a-p  \mwedge{}  b-c-q)  {}\mRightarrow{}  pac  \mcong{}\msuba{}  qca))))
Date html generated:
2020_05_20-AM-10_33_46
Last ObjectModification:
2020_01_27-PM-09_59_22
Theory : euclidean!plane!geometry
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