Nuprl Lemma : lsep-colinear
∀g:EuclideanPlane. ∀p,a,b,x,y:Point.  (p # ab 
⇒ x ≠ y 
⇒ Colinear(x;a;b) 
⇒ Colinear(y;a;b) 
⇒ p # xy)
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]
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
cand: A c∧ B
, 
oriented-plane: OrientedPlane
, 
uall: ∀[x:A]. B[x]
, 
subtype_rel: A ⊆r B
, 
exists: ∃x:A. B[x]
, 
or: P ∨ Q
, 
prop: ℙ
, 
guard: {T}
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
append: as @ bs
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
top: Top
, 
so_apply: x[s1;s2;s3]
, 
geo-colinear-set: geo-colinear-set(e; L)
, 
l_all: (∀x∈L.P[x])
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
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
, 
uimplies: b supposing a
Lemmas referenced : 
lsep-iff-all-sep, 
oriented-colinear-append, 
cons_wf, 
geo-point_wf, 
nil_wf, 
cons_member, 
l_member_wf, 
equal_wf, 
geo-sep_wf, 
exists_wf, 
geo-colinear-is-colinear-set, 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
length_of_cons_lemma, 
length_of_nil_lemma, 
false_wf, 
lelt_wf, 
geo-colinear_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
subtype_rel_transitivity, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-lsep_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
productElimination, 
independent_functionElimination, 
sqequalRule, 
isectElimination, 
applyEquality, 
because_Cache, 
dependent_pairFormation, 
independent_pairFormation, 
inlFormation, 
inrFormation, 
productEquality, 
lambdaEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
dependent_set_memberEquality, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
instantiate, 
independent_isectElimination
Latex:
\mforall{}g:EuclideanPlane.  \mforall{}p,a,b,x,y:Point.
    (p  \#  ab  {}\mRightarrow{}  x  \mneq{}  y  {}\mRightarrow{}  Colinear(x;a;b)  {}\mRightarrow{}  Colinear(y;a;b)  {}\mRightarrow{}  p  \#  xy)
Date html generated:
2018_05_22-PM-00_08_56
Last ObjectModification:
2018_04_04-PM-05_46_36
Theory : euclidean!plane!geometry
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