Nuprl Lemma : left-right-sep
∀g:OrientedPlane. ∀a,b,c,d:Point.  (a leftof cd ⇒ b leftof dc ⇒ a ≠ b)
Proof
Definitions occuring in Statement : 
oriented-plane: OrientedPlane, 
geo-left: a leftof bc, 
geo-sep: a ≠ b, 
geo-point: Point, 
all: ∀x:A. B[x], 
implies: P ⇒ Q
Definitions unfolded in proof : 
guard: {T}, 
oriented-plane: Error :oriented-plane, 
prop: ℙ, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
subtype_rel: A ⊆r B, 
and: P ∧ Q, 
exists: ∃x:A. B[x], 
member: t ∈ T, 
implies: P ⇒ Q, 
all: ∀x:A. B[x], 
or: P ∨ Q, 
geo-lsep: a # bc, 
false: False, 
cand: A c∧ B, 
not: ¬A, 
geo-colinear: Colinear(a;b;c)
Lemmas referenced : 
Error :basic-geo-primitives_wf, 
Error :basic-geo-structure_wf, 
Error :o-geo-structure_wf, 
Error :oriented-plane_wf, 
subtype_rel_transitivity, 
Error :oriented-plane-subtype1, 
Error :o-geo-structure-subtype, 
geo-point_wf, 
geo-left_wf, 
geo-between-sep, 
Error :oriented-plane-subtype, 
geo-between-symmetry, 
geo-sep-sym, 
Error :use-plane-sep, 
geo-between_wf, 
not_wf, 
lsep-colinear-sep
Rules used in proof : 
instantiate, 
rename, 
setElimination, 
independent_isectElimination, 
isectElimination, 
sqequalRule, 
applyEquality, 
because_Cache, 
productElimination, 
hypothesis, 
independent_functionElimination, 
hypothesisEquality, 
thin, 
dependent_functionElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
inrFormation, 
productEquality, 
voidElimination, 
independent_pairFormation
Latex:
\mforall{}g:OrientedPlane.  \mforall{}a,b,c,d:Point.    (a  leftof  cd  {}\mRightarrow{}  b  leftof  dc  {}\mRightarrow{}  a  \mneq{}  b)
Date html generated:
2017_10_02-PM-04_47_33
Last ObjectModification:
2017_08_05-AM-10_20_16
Theory : euclidean!plane!geometry
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