Nuprl Lemma : pgeo-three-points-axiom
∀g:ProjectivePlaneStructure. ∀l:Line.  ∃a,b,c:Point. (a I l ∧ b I l ∧ c I l ∧ a ≠ b ∧ b ≠ c ∧ c ≠ a)
Proof
Definitions occuring in Statement : 
projective-plane-structure: ProjectivePlaneStructure
, 
pgeo-psep: a ≠ b
, 
pgeo-incident: a I b
, 
pgeo-line: Line
, 
pgeo-point: Point
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
and: P ∧ Q
Definitions unfolded in proof : 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
Lemmas referenced : 
projective-plane-structure_wf, 
projective-plane-structure_subtype, 
pgeo-line_wf, 
pgeo-three-points_wf
Rules used in proof : 
sqequalRule, 
applyEquality, 
isectElimination, 
hypothesis, 
hypothesisEquality, 
thin, 
dependent_functionElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
cut, 
introduction, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}g:ProjectivePlaneStructure.  \mforall{}l:Line.    \mexists{}a,b,c:Point.  (a  I  l  \mwedge{}  b  I  l  \mwedge{}  c  I  l  \mwedge{}  a  \mneq{}  b  \mwedge{}  b  \mneq{}  c  \mwedge{}  c  \mneq{}  a)
Date html generated:
2018_05_22-PM-00_31_50
Last ObjectModification:
2017_11_27-PM-04_19_05
Theory : euclidean!plane!geometry
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