Nuprl Lemma : geo-perp-in-symmetry
∀e:BasicGeometry. ∀x:Point.
  ∀[a,b,c,d:Point].  (ab  ⊥x cd 
⇒ {ba  ⊥x cd ∧ ab  ⊥x dc ∧ ba  ⊥x dc ∧ cd  ⊥x ab ∧ dc  ⊥x ab ∧ cd  ⊥x ba ∧ dc  ⊥x ba})
Proof
Definitions occuring in Statement : 
geo-perp-in: ab  ⊥x cd
, 
basic-geometry: BasicGeometry
, 
geo-point: Point
, 
uall: ∀[x:A]. B[x]
, 
guard: {T}
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
uall: ∀[x:A]. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
guard: {T}
, 
and: P ∧ Q
, 
cand: A c∧ B
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
uimplies: b supposing a
Lemmas referenced : 
geo-perp-in-symmetry1, 
geo-perp-in-symmetry2, 
geo-perp-in_wf, 
geo-point_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
basic-geometry-subtype, 
subtype_rel_transitivity, 
basic-geometry_wf, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
isect_memberFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
because_Cache, 
independent_pairFormation, 
hypothesis, 
isectElimination, 
applyEquality, 
instantiate, 
independent_isectElimination, 
sqequalRule, 
independent_functionElimination
Latex:
\mforall{}e:BasicGeometry.  \mforall{}x:Point.
    \mforall{}[a,b,c,d:Point].
        (ab    \mbot{}x  cd
        {}\mRightarrow{}  \{ba    \mbot{}x  cd  \mwedge{}  ab    \mbot{}x  dc  \mwedge{}  ba    \mbot{}x  dc  \mwedge{}  cd    \mbot{}x  ab  \mwedge{}  dc    \mbot{}x  ab  \mwedge{}  cd    \mbot{}x  ba  \mwedge{}  dc    \mbot{}x  ba\})
Date html generated:
2018_05_22-PM-00_04_32
Last ObjectModification:
2018_04_18-PM-09_59_25
Theory : euclidean!plane!geometry
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