Nuprl Lemma : Mid_cases
∀e:BasicGeometry. ∀A,B,C:Point.  ((B=A=C ∨ C=A=B) 
⇒ B=A=C)
Proof
Definitions occuring in Statement : 
geo-midpoint: a=m=b
, 
basic-geometry: BasicGeometry
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
or: P ∨ Q
Definitions unfolded in proof : 
uimplies: b supposing a
, 
guard: {T}
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
member: t ∈ T
, 
or: P ∨ Q
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
Lemmas referenced : 
Error :basic-geo-primitives_wf, 
Error :basic-geo-structure_wf, 
basic-geometry_wf, 
subtype_rel_transitivity, 
basic-geometry-subtype, 
geo-point_wf, 
geo-midpoint_wf, 
or_wf, 
geo-midpoint-symmetry
Rules used in proof : 
because_Cache, 
sqequalRule, 
independent_isectElimination, 
instantiate, 
applyEquality, 
isectElimination, 
independent_functionElimination, 
hypothesisEquality, 
dependent_functionElimination, 
extract_by_obid, 
introduction, 
cut, 
hypothesis, 
thin, 
unionElimination, 
sqequalHypSubstitution, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}e:BasicGeometry.  \mforall{}A,B,C:Point.    ((B=A=C  \mvee{}  C=A=B)  {}\mRightarrow{}  B=A=C)
Date html generated:
2017_10_02-PM-06_33_40
Last ObjectModification:
2017_08_05-PM-04_43_54
Theory : euclidean!plane!geometry
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