Nuprl Lemma : geo-between-middle-or
∀e:BasicGeometry. ∀a,b,c,d:Point.  (a ≠ b 
⇒ b ≠ c 
⇒ b ≠ d 
⇒ a_b_d 
⇒ a_c_d 
⇒ (b_c_d ∨ c_b_d))
Proof
Definitions occuring in Statement : 
basic-geometry: BasicGeometry
, 
geo-between: a_b_c
, 
geo-sep: a ≠ b
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
or: 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
, 
guard: {T}
, 
uimplies: b supposing a
, 
prop: ℙ
, 
and: P ∧ Q
, 
not: ¬A
, 
false: False
, 
or: P ∨ Q
, 
iff: P 
⇐⇒ Q
, 
basic-geometry: BasicGeometry
, 
euclidean-plane: EuclideanPlane
, 
basic-geometry-: BasicGeometry-
, 
exists: ∃x:A. B[x]
, 
stable: Stable{P}
, 
geo-eq: a ≡ b
, 
cand: A c∧ B
Lemmas referenced : 
geo-between_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-sep_wf, 
geo-point_wf, 
geo-sep-sym, 
geo-strict-between-sep3, 
iff_weakening_uiff, 
not_wf, 
not_over_or, 
istype-void, 
geo-between-middle, 
geo-between-sep, 
geo-sep-or, 
geo-strict-between-sep1, 
subtype_rel_self, 
basic-geometry-_wf, 
geo-proper-extend-exists, 
stable__geo-between, 
double-negation-hyp-elim, 
geo-construction-unicity, 
geo-between-symmetry, 
geo-strict-between-implies-between, 
geo-between-inner-trans, 
extended-out-preserves-between, 
geo-out-iff-between1, 
euclidean-plane-axioms
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
universeIsType, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
applyEquality, 
hypothesis, 
instantiate, 
independent_isectElimination, 
sqequalRule, 
because_Cache, 
inhabitedIsType, 
productElimination, 
dependent_functionElimination, 
independent_functionElimination, 
unionEquality, 
productEquality, 
voidElimination, 
functionIsType, 
unionIsType, 
productIsType, 
setElimination, 
rename, 
dependent_set_memberEquality_alt, 
unionElimination, 
inrFormation_alt, 
inlFormation_alt, 
independent_pairFormation
Latex:
\mforall{}e:BasicGeometry.  \mforall{}a,b,c,d:Point.    (a  \mneq{}  b  {}\mRightarrow{}  b  \mneq{}  c  {}\mRightarrow{}  b  \mneq{}  d  {}\mRightarrow{}  a\_b\_d  {}\mRightarrow{}  a\_c\_d  {}\mRightarrow{}  (b\_c\_d  \mvee{}  c\_b\_d))
Date html generated:
2019_10_16-PM-01_24_49
Last ObjectModification:
2019_01_13-PM-00_56_38
Theory : euclidean!plane!geometry
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