Nuprl Lemma : pgeo-peq-preserves-incidence
∀g:ProjectivePlane. ∀a,b:Point. ∀l:Line.  (a I l ⇒ a ≡ b ⇒ b I l)
Proof
Definitions occuring in Statement : 
projective-plane: ProjectivePlane, 
pgeo-peq: a ≡ b, 
pgeo-incident: a I b, 
pgeo-line: Line, 
pgeo-point: Point, 
all: ∀x:A. B[x], 
implies: P ⇒ Q
Definitions unfolded in proof : 
uimplies: b supposing a, 
guard: {T}, 
false: False, 
subtype_rel: A ⊆r B, 
uall: ∀[x:A]. B[x], 
prop: ℙ, 
cand: A c∧ B, 
and: P ∧ Q, 
member: t ∈ T, 
exists: ∃x:A. B[x], 
pgeo-psep: a ≠ b, 
pgeo-peq: a ≡ b, 
not: ¬A, 
pgeo-incident: a I b, 
implies: P ⇒ Q, 
all: ∀x:A. B[x]
Lemmas referenced : 
pgeo-point_wf, 
pgeo-line_wf, 
pgeo-primitives_wf, 
projective-plane-structure_wf, 
basic-projective-plane_wf, 
projective-plane_wf, 
subtype_rel_transitivity, 
projective-plane-subtype, 
basic-projective-plane-subtype, 
projective-plane-structure_subtype, 
pgeo-peq_wf, 
pgeo-plsep_wf, 
pgeo-incident_wf
Rules used in proof : 
independent_isectElimination, 
instantiate, 
voidElimination, 
sqequalRule, 
because_Cache, 
applyEquality, 
isectElimination, 
extract_by_obid, 
introduction, 
productEquality, 
independent_pairFormation, 
hypothesis, 
cut, 
hypothesisEquality, 
dependent_pairFormation, 
thin, 
independent_functionElimination, 
sqequalHypSubstitution, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}g:ProjectivePlane.  \mforall{}a,b:Point.  \mforall{}l:Line.    (a  I  l  {}\mRightarrow{}  a  \mequiv{}  b  {}\mRightarrow{}  b  I  l)
Date html generated:
2018_05_22-PM-00_43_55
Last ObjectModification:
2017_11_17-PM-00_07_50
Theory : euclidean!plane!geometry
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