Nuprl Lemma : geo-midpoint_functionality
∀e:BasicGeometry. ∀m,a,b,m',a',b':Point.  (m ≡ m' 
⇒ a ≡ a' 
⇒ b ≡ b' 
⇒ {a=m=b 
⇒ a'=m'=b'})
Proof
Definitions occuring in Statement : 
geo-midpoint: a=m=b
, 
basic-geometry: BasicGeometry
, 
geo-eq: a ≡ b
, 
geo-point: Point
, 
guard: {T}
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
uimplies: b supposing a
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
member: t ∈ T
, 
cand: A c∧ B
, 
and: P ∧ Q
, 
implies: P 
⇒ Q
, 
all: ∀x:A. B[x]
, 
guard: {T}
, 
geo-midpoint: a=m=b
, 
iff: P 
⇐⇒ Q
Lemmas referenced : 
geo-point_wf, 
geo-eq_wf, 
geo-congruent_wf, 
Error :basic-geo-primitives_wf, 
Error :basic-geo-structure_wf, 
basic-geometry_wf, 
subtype_rel_transitivity, 
basic-geometry-subtype, 
geo-between_wf, 
geo-between_functionality, 
geo-eq_weakening, 
geo-congruent_functionality
Rules used in proof : 
because_Cache, 
independent_isectElimination, 
instantiate, 
applyEquality, 
hypothesisEquality, 
isectElimination, 
extract_by_obid, 
introduction, 
productEquality, 
hypothesis, 
independent_pairFormation, 
cut, 
thin, 
productElimination, 
sqequalHypSubstitution, 
lambdaFormation, 
computationStep, 
sqequalTransitivity, 
sqequalReflexivity, 
sqequalRule, 
sqequalSubstitution, 
independent_functionElimination, 
dependent_functionElimination
Latex:
\mforall{}e:BasicGeometry.  \mforall{}m,a,b,m',a',b':Point.    (m  \mequiv{}  m'  {}\mRightarrow{}  a  \mequiv{}  a'  {}\mRightarrow{}  b  \mequiv{}  b'  {}\mRightarrow{}  \{a=m=b  {}\mRightarrow{}  a'=m'=b'\})
Date html generated:
2017_10_02-PM-04_45_45
Last ObjectModification:
2017_08_05-AM-11_45_50
Theory : euclidean!plane!geometry
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