Nuprl Lemma : half-plane-point-exists
∀g:EuclideanPlane. ∀x,y:Point.  (x ≠ y 
⇒ (∃q:Point. q leftof xy))
Proof
Definitions occuring in Statement : 
euclidean-plane: EuclideanPlane
, 
geo-left: a leftof bc
, 
geo-sep: a ≠ b
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
subtype_rel: A ⊆r B
, 
prop: ℙ
, 
sq_exists: ∃x:A [B[x]]
, 
and: P ∧ Q
, 
guard: {T}
, 
uimplies: b supposing a
, 
euclidean-plane: EuclideanPlane
, 
sq_stable: SqStable(P)
, 
squash: ↓T
, 
exists: ∃x:A. B[x]
Lemmas referenced : 
Euclid-Prop1-left, 
geo-sep_wf, 
sq_stable__and, 
geo-congruent_wf, 
geo-left_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
subtype_rel_transitivity, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
sq_stable__geo-congruent, 
sq_stable__geo-left, 
geo-point_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
dependent_set_memberEquality_alt, 
hypothesis, 
universeIsType, 
isectElimination, 
applyEquality, 
because_Cache, 
sqequalRule, 
setElimination, 
rename, 
productEquality, 
productElimination, 
isect_memberEquality_alt, 
instantiate, 
independent_isectElimination, 
productIsType, 
inhabitedIsType, 
independent_functionElimination, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
dependent_pairFormation_alt
Latex:
\mforall{}g:EuclideanPlane.  \mforall{}x,y:Point.    (x  \mneq{}  y  {}\mRightarrow{}  (\mexists{}q:Point.  q  leftof  xy))
Date html generated:
2019_10_16-PM-01_48_35
Last ObjectModification:
2018_11_05-PM-09_17_41
Theory : euclidean!plane!geometry
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