Nuprl Lemma : pgeo-join-plsep-sym
∀pg:ProjectivePlane. ∀a,b,c:Point. ∀s:a ≠ b. ∀s2:b ≠ a.  (c ≠ a ∨ b 
⇒ c ≠ b ∨ a)
Proof
Definitions occuring in Statement : 
projective-plane: ProjectivePlane
, 
pgeo-join: p ∨ q
, 
pgeo-psep: a ≠ b
, 
pgeo-plsep: a ≠ b
, 
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
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
guard: {T}
, 
uimplies: b supposing a
, 
and: P ∧ Q
, 
prop: ℙ
, 
or: P ∨ Q
, 
pgeo-lsep: l ≠ m
, 
exists: ∃x:A. B[x]
, 
pgeo-incident: a I b
, 
not: ¬A
, 
false: False
Lemmas referenced : 
PL-sep-or, 
pgeo-join_wf, 
projective-plane-structure-complete_subtype, 
projective-plane-subtype, 
subtype_rel_transitivity, 
projective-plane_wf, 
projective-plane-structure-complete_wf, 
projective-plane-structure_wf, 
pgeo-line_wf, 
pgeo-incident_wf, 
pgeo-join-lsep-sym, 
pgeo-plsep_wf, 
projective-plane-structure_subtype, 
pgeo-primitives_wf, 
pgeo-psep_wf, 
pgeo-point_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
because_Cache, 
hypothesisEquality, 
applyEquality, 
hypothesis, 
instantiate, 
isectElimination, 
independent_isectElimination, 
sqequalRule, 
lambdaEquality, 
setElimination, 
rename, 
setEquality, 
productEquality, 
independent_functionElimination, 
unionElimination, 
productElimination, 
voidElimination
Latex:
\mforall{}pg:ProjectivePlane.  \mforall{}a,b,c:Point.  \mforall{}s:a  \mneq{}  b.  \mforall{}s2:b  \mneq{}  a.    (c  \mneq{}  a  \mvee{}  b  {}\mRightarrow{}  c  \mneq{}  b  \mvee{}  a)
Date html generated:
2018_05_22-PM-00_49_01
Last ObjectModification:
2017_12_05-AM-11_23_23
Theory : euclidean!plane!geometry
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