Nuprl Lemma : colinear-cong3
∀e:EuclideanPlane. ∀a,b,c,x,y:Point.
  (a ≠ b 
⇒ Colinear(a;b;c) 
⇒ ab ≅ xy 
⇒ (∃z:Point. (Colinear(x;y;z) ∧ Cong3(abc,xyz))))
Proof
Definitions occuring in Statement : 
geo-cong-tri: Cong3(abc,a'b'c')
, 
euclidean-plane: EuclideanPlane
, 
geo-colinear: Colinear(a;b;c)
, 
geo-congruent: ab ≅ cd
, 
geo-sep: a ≠ b
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
member: t ∈ T
, 
or: P ∨ Q
, 
prop: ℙ
, 
uall: ∀[x:A]. B[x]
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
uimplies: b supposing a
, 
basic-geometry: BasicGeometry
, 
exists: ∃x:A. B[x]
, 
geo-midpoint: a=m=b
, 
and: P ∧ Q
, 
cand: A c∧ B
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
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])
, 
select: L[n]
, 
cons: [a / b]
, 
subtract: n - m
, 
geo-cong-tri: Cong3(abc,a'b'c')
, 
uiff: uiff(P;Q)
, 
euclidean-plane: EuclideanPlane
, 
not: ¬A
, 
false: False
, 
stable: Stable{P}
, 
squash: ↓T
, 
true: True
, 
int_seg: {i..j-}
, 
lelt: i ≤ j < k
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
less_than: a < b
Lemmas referenced : 
geo-colinear-sep-cases, 
geo-congruent_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
subtype_rel_transitivity, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-colinear_wf, 
geo-sep_wf, 
geo-point_wf, 
symmetric-point-construction, 
geo-congruent-symmetry, 
geo-congruent-sep, 
geo-extend-exists, 
geo-sep-sym, 
oriented-colinear-append, 
cons_member, 
geo-colinear-is-colinear-set, 
geo-between-implies-colinear, 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
geo-congruent-iff-length, 
geo-length-flip, 
geo-cong-tri_wf, 
geo-between-symmetry, 
geo-between-same-side2, 
stable__geo-congruent, 
false_wf, 
or_wf, 
geo-between_wf, 
not_wf, 
minimal-double-negation-hyp-elim, 
minimal-not-not-excluded-middle, 
and_wf, 
equal_wf, 
geo-length-type_wf, 
geo-add-length_wf, 
geo-length_wf, 
geo-mk-seg_wf, 
geo-add-length-between, 
geo-add-length-cancel-left, 
squash_wf, 
true_wf, 
basic-geometry_wf, 
geo-add-length-assoc, 
subtype_rel_self, 
iff_weakening_equal, 
geo-add-length-implies-eq-zero, 
geo-add-length-is-zero, 
length_of_cons_lemma, 
length_of_nil_lemma, 
lelt_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
dependent_functionElimination, 
thin, 
because_Cache, 
hypothesisEquality, 
independent_functionElimination, 
hypothesis, 
unionElimination, 
isectElimination, 
applyEquality, 
instantiate, 
independent_isectElimination, 
sqequalRule, 
productElimination, 
rename, 
dependent_pairFormation, 
independent_pairFormation, 
inrFormation, 
inlFormation, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
equalityTransitivity, 
equalitySymmetry, 
productEquality, 
setElimination, 
functionEquality, 
dependent_set_memberEquality, 
applyLambdaEquality, 
lambdaEquality, 
imageElimination, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
universeEquality
Latex:
\mforall{}e:EuclideanPlane.  \mforall{}a,b,c,x,y:Point.
    (a  \mneq{}  b  {}\mRightarrow{}  Colinear(a;b;c)  {}\mRightarrow{}  ab  \mcong{}  xy  {}\mRightarrow{}  (\mexists{}z:Point.  (Colinear(x;y;z)  \mwedge{}  Cong3(abc,xyz))))
Date html generated:
2018_05_22-PM-00_15_42
Last ObjectModification:
2018_04_05-AM-01_03_23
Theory : euclidean!plane!geometry
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