Nuprl Lemma : use-triangle-axiom2
∀g:ProjectivePlane. ∀p,q:Point. ∀l,m:Line. ∀s:p ≠ q. ∀s1:l ≠ m.  (p ≠ l 
⇒ q ≠ m 
⇒ p I m 
⇒ q I l 
⇒ l ∧ m ≠ p ∨ q)
Proof
Definitions occuring in Statement : 
projective-plane: ProjectivePlane
, 
pgeo-meet: l ∧ m
, 
pgeo-join: p ∨ q
, 
pgeo-lsep: l ≠ m
, 
pgeo-psep: a ≠ b
, 
pgeo-incident: a I b
, 
pgeo-plsep: a ≠ b
, 
pgeo-line: Line
, 
pgeo-point: Point
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
and: P ∧ Q
, 
prop: ℙ
, 
uall: ∀[x:A]. B[x]
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
uimplies: b supposing a
Lemmas referenced : 
pgeo-incident_wf, 
projective-plane-structure_subtype, 
basic-projective-plane-subtype, 
projective-plane-subtype, 
subtype_rel_transitivity, 
projective-plane_wf, 
basic-projective-plane_wf, 
projective-plane-structure_wf, 
pgeo-primitives_wf, 
pgeo-plsep_wf, 
pgeo-lsep_wf, 
pgeo-psep_wf, 
pgeo-line_wf, 
pgeo-point_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
productElimination, 
isectElimination, 
applyEquality, 
hypothesis, 
instantiate, 
independent_isectElimination, 
sqequalRule, 
because_Cache, 
independent_functionElimination
Latex:
\mforall{}g:ProjectivePlane.  \mforall{}p,q:Point.  \mforall{}l,m:Line.  \mforall{}s:p  \mneq{}  q.  \mforall{}s1:l  \mneq{}  m.
    (p  \mneq{}  l  {}\mRightarrow{}  q  \mneq{}  m  {}\mRightarrow{}  p  I  m  {}\mRightarrow{}  q  I  l  {}\mRightarrow{}  l  \mwedge{}  m  \mneq{}  p  \mvee{}  q)
Date html generated:
2018_05_22-PM-00_41_43
Last ObjectModification:
2017_11_10-PM-03_40_08
Theory : euclidean!plane!geometry
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