Nuprl Lemma : Unique
∀g:BasicProjectivePlane. ∀[l,m:Line]. ∀[p,q:Point].  ¬((¬p ≡ q) ∧ (¬l ≡ m)) supposing p I l ∧ q I l ∧ p I m ∧ q I m
Proof
Definitions occuring in Statement : 
basic-projective-plane: BasicProjectivePlane
, 
pgeo-leq: a ≡ b
, 
pgeo-peq: a ≡ b
, 
pgeo-incident: a I b
, 
pgeo-line: Line
, 
pgeo-point: Point
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
not: ¬A
, 
and: P ∧ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
false: False
, 
and: P ∧ Q
, 
cand: A c∧ B
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
guard: {T}
Lemmas referenced : 
basic-projective-plane-axioms, 
not_wf, 
pgeo-peq_wf, 
pgeo-leq_wf, 
pgeo-incident_wf, 
projective-plane-structure_subtype, 
basic-projective-plane-subtype, 
subtype_rel_transitivity, 
basic-projective-plane_wf, 
projective-plane-structure_wf, 
pgeo-primitives_wf, 
pgeo-point_wf, 
pgeo-line_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
isect_memberFormation, 
introduction, 
cut, 
thin, 
sqequalHypSubstitution, 
productElimination, 
extract_by_obid, 
dependent_functionElimination, 
hypothesisEquality, 
hypothesis, 
independent_functionElimination, 
voidElimination, 
because_Cache, 
productEquality, 
isectElimination, 
applyEquality, 
sqequalRule, 
lambdaEquality, 
instantiate, 
independent_isectElimination, 
isect_memberEquality, 
equalityTransitivity, 
equalitySymmetry
Latex:
\mforall{}g:BasicProjectivePlane
    \mforall{}[l,m:Line].  \mforall{}[p,q:Point].    \mneg{}((\mneg{}p  \mequiv{}  q)  \mwedge{}  (\mneg{}l  \mequiv{}  m))  supposing  p  I  l  \mwedge{}  q  I  l  \mwedge{}  p  I  m  \mwedge{}  q  I  m
Date html generated:
2018_05_22-PM-00_34_43
Last ObjectModification:
2017_11_10-PM-03_46_45
Theory : euclidean!plane!geometry
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