Nuprl Lemma : colinear-lsep'
∀g:OrientedPlane. ∀a,b,c,y:Point.  (y # ab ⇒ b ≠ c ⇒ Colinear(a;b;c) ⇒ y # cb)
Proof
Definitions occuring in Statement : 
oriented-plane: OrientedPlane, 
geo-lsep: a # bc, 
geo-colinear: Colinear(a;b;c), 
geo-sep: a ≠ b, 
geo-point: Point, 
all: ∀x:A. B[x], 
implies: P ⇒ Q
Definitions unfolded in proof : 
uimplies: b supposing a, 
subtype_rel: A ⊆r B, 
uall: ∀[x:A]. B[x], 
prop: ℙ, 
subtract: n - m, 
cons: [a / b], 
select: L[n], 
l_all: (∀x∈L.P[x]), 
geo-colinear-set: geo-colinear-set(e; L), 
cand: A c∧ B, 
and: P ∧ Q, 
guard: {T}, 
member: t ∈ T, 
implies: P ⇒ Q, 
all: ∀x:A. B[x], 
oriented-plane: OrientedPlane
Lemmas referenced : 
geo-point_wf, 
geo-lsep_wf, 
geo-sep_wf, 
geo-primitives_wf, 
euclidean-plane-structure_wf, 
euclidean-plane_wf, 
oriented-plane_wf, 
subtype_rel_transitivity, 
oriented-plane-subtype, 
euclidean-plane-subtype, 
euclidean-plane-structure-subtype, 
geo-colinear_wf, 
geo-colinear-is-colinear-set, 
geo-sep-sym, 
lsep-all-sym, 
colinear-lsep
Rules used in proof : 
independent_isectElimination, 
instantiate, 
applyEquality, 
isectElimination, 
sqequalRule, 
productElimination, 
hypothesis, 
independent_functionElimination, 
hypothesisEquality, 
because_Cache, 
thin, 
dependent_functionElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}g:OrientedPlane.  \mforall{}a,b,c,y:Point.    (y  \#  ab  {}\mRightarrow{}  b  \mneq{}  c  {}\mRightarrow{}  Colinear(a;b;c)  {}\mRightarrow{}  y  \#  cb)
Date html generated:
2017_10_02-PM-04_47_07
Last ObjectModification:
2017_08_08-PM-00_34_39
Theory : euclidean!plane!geometry
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