Nuprl Lemma : not-lsep-iff-colinear
∀g:EuclideanPlane. ∀a,b,c:Point.  (¬a # bc ⇐⇒ Colinear(a;b;c))
Proof
Definitions occuring in Statement : 
euclidean-plane: EuclideanPlane, 
geo-lsep: a # bc, 
geo-colinear: Colinear(a;b;c), 
geo-point: Point, 
all: ∀x:A. B[x], 
iff: P ⇐⇒ Q, 
not: ¬A
Definitions unfolded in proof : 
cand: A c∧ B, 
and: P ∧ Q, 
member: t ∈ T, 
all: ∀x:A. B[x]
Lemmas referenced : 
euclidean-plane_wf, 
euclidean-plane-axioms
Rules used in proof : 
productElimination, 
hypothesisEquality, 
thin, 
dependent_functionElimination, 
sqequalHypSubstitution, 
hypothesis, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
extract_by_obid, 
introduction, 
cut
Latex:
\mforall{}g:EuclideanPlane.  \mforall{}a,b,c:Point.    (\mneg{}a  \#  bc  \mLeftarrow{}{}\mRightarrow{}  Colinear(a;b;c))
Date html generated:
2017_10_02-PM-03_29_21
Last ObjectModification:
2017_08_07-AM-10_45_42
Theory : euclidean!plane!geometry
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