Nuprl Lemma : geo-out-strict_transitivity
∀e:BasicGeometry. ∀a,b,c,d:Point.
  (b ≠ d 
⇒ geo-out-strict(e;a;b;c) 
⇒ geo-out-strict(e;a;c;d) 
⇒ geo-out-strict(e;a;b;d))
Proof
Definitions occuring in Statement : 
geo-out-strict: geo-out-strict(e;p;a;b)
, 
basic-geometry: BasicGeometry
, 
geo-sep: a ≠ b
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
geo-out-strict: geo-out-strict(e;p;a;b)
, 
not: ¬A
, 
and: P ∧ Q
, 
member: t ∈ T
, 
subtype_rel: A ⊆r B
, 
basic-geometry: BasicGeometry
, 
euclidean-plane: EuclideanPlane
, 
basic-geometry-: BasicGeometry-
, 
uall: ∀[x:A]. B[x]
, 
false: False
, 
prop: ℙ
, 
guard: {T}
, 
uimplies: b supposing a
, 
geo-strict-between: a-b-c
, 
cand: A c∧ B
Lemmas referenced : 
geo-strict-between-sym, 
subtype_rel_self, 
basic-geometry-_wf, 
geo-strict-between-trans, 
geo-strict-between-trans2, 
geo-strict-between-trans3, 
geo-strict-between_wf, 
istype-void, 
geo-out-strict_wf, 
geo-sep_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
basic-geometry-subtype, 
subtype_rel_transitivity, 
basic-geometry_wf, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-point_wf, 
geo-between-same-side, 
geo-strict-between-implies-between, 
geo-strict-between-sep2, 
geo-between_wf, 
geo-strict-between-sep1, 
geo-sep-sym, 
geo-between-middle, 
geo-between-symmetry, 
geo-between-inner-trans
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
sqequalHypSubstitution, 
productElimination, 
thin, 
independent_functionElimination, 
independent_pairFormation, 
cut, 
hypothesis, 
introduction, 
extract_by_obid, 
dependent_functionElimination, 
hypothesisEquality, 
applyEquality, 
sqequalRule, 
instantiate, 
isectElimination, 
because_Cache, 
voidElimination, 
universeIsType, 
productIsType, 
functionIsType, 
independent_isectElimination, 
inhabitedIsType
Latex:
\mforall{}e:BasicGeometry.  \mforall{}a,b,c,d:Point.
    (b  \mneq{}  d  {}\mRightarrow{}  geo-out-strict(e;a;b;c)  {}\mRightarrow{}  geo-out-strict(e;a;c;d)  {}\mRightarrow{}  geo-out-strict(e;a;b;d))
Date html generated:
2019_10_16-PM-01_23_00
Last ObjectModification:
2019_08_27-AM-08_00_41
Theory : euclidean!plane!geometry
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