Nuprl Lemma : lsep-implies-sep-or-not-colinear
∀e:EuclideanPlane. ∀a,b,c,x:Point.  (a # bc 
⇒ (c ≠ x ∨ (¬Colinear(a;b;x))))
Proof
Definitions occuring in Statement : 
euclidean-plane: EuclideanPlane
, 
geo-lsep: a # bc
, 
geo-colinear: Colinear(a;b;c)
, 
geo-sep: a ≠ b
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
not: ¬A
, 
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
, 
oriented-plane: OrientedPlane
, 
geo-colinear-set: geo-colinear-set(e; L)
, 
l_all: (∀x∈L.P[x])
, 
top: Top
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
false: False
, 
not: ¬A
, 
less_than: a < b
, 
squash: ↓T
, 
true: True
, 
select: L[n]
, 
cons: [a / b]
, 
subtract: n - m
, 
cand: A c∧ B
, 
euclidean-plane: EuclideanPlane
, 
or: P ∨ Q
, 
basic-geometry: BasicGeometry
, 
exists: ∃x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
append: as @ bs
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
so_apply: x[s1;s2;s3]
, 
basic-geometry-: BasicGeometry-
, 
geo-eq: a ≡ b
, 
geo-strict-between: a-b-c
, 
uiff: uiff(P;Q)
, 
stable: Stable{P}
, 
geo-gt: cd > ab
Lemmas referenced : 
geo-lsep_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
subtype_rel_transitivity, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-point_wf, 
lsep-colinear-sep1, 
geo-colinear-is-colinear-set, 
length_of_cons_lemma, 
istype-void, 
length_of_nil_lemma, 
istype-false, 
istype-le, 
istype-less_than, 
geo-colinear_wf, 
lsep-all-sym, 
euclidean-plane-axioms, 
geo-sep-or, 
lsep-implies-sep, 
geo-sep_wf, 
geo-sep-sym, 
geo-strict-between-sep3, 
geo-proper-extend-exists, 
geo-strict-between-implies-colinear, 
oriented-colinear-append, 
cons_wf, 
nil_wf, 
cons_member, 
l_member_wf, 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
geo-colinear-cases, 
false_wf, 
stable__false, 
geo-eq_wf, 
geo-strict-between_wf, 
geo-construction-unicity, 
geo-strict-between-implies-between, 
geo-congruent-iff-length, 
not_wf, 
minimal-double-negation-hyp-elim, 
geo-sep_functionality, 
geo-eq_weakening, 
geo-congruent_functionality, 
geo-strict-between_functionality, 
minimal-not-not-excluded-middle, 
geo-between-same-side-or, 
geo-between-exchange3, 
geo-between-exchange4, 
geo-between-symmetry, 
geo-between-outer-trans, 
geo-between-inner-trans, 
geo-congruent-refl, 
geo-between_wf, 
geo-congruent_wf, 
geo-le-from-be, 
geo-lt_wf, 
geo-length_wf, 
geo-mk-seg_wf, 
geo-gt-implies-lt, 
not-lt-and-symm-le, 
geo-between-congruent, 
geo-between_functionality
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, 
inhabitedIsType, 
because_Cache, 
dependent_functionElimination, 
dependent_set_memberEquality_alt, 
independent_functionElimination, 
isect_memberEquality_alt, 
voidElimination, 
natural_numberEquality, 
independent_pairFormation, 
imageMemberEquality, 
baseClosed, 
productIsType, 
productElimination, 
setElimination, 
rename, 
unionElimination, 
inlFormation_alt, 
functionIsType, 
dependent_pairFormation_alt, 
inrFormation_alt, 
equalityIstype, 
equalitySymmetry, 
unionEquality, 
functionEquality, 
unionIsType, 
hyp_replacement, 
equalityTransitivity, 
applyLambdaEquality
Latex:
\mforall{}e:EuclideanPlane.  \mforall{}a,b,c,x:Point.    (a  \#  bc  {}\mRightarrow{}  (c  \mneq{}  x  \mvee{}  (\mneg{}Colinear(a;b;x))))
Date html generated:
2019_10_16-PM-02_56_01
Last ObjectModification:
2018_12_05-PM-10_06_04
Theory : euclidean!plane!geometry
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