Nuprl Lemma : not-perp-point-construction-between
∀e:HeytingGeometry. ∀a,b,c:Point.  (a # bc ⇒ (∃c',b':Point. ((c=c'=b' ∧ ab' ≅ ac) ∧ b-a-b' ∧ a # c'b' ∧ Rac'b')))
Proof
Definitions occuring in Statement : 
geo-triangle: a # bc, 
heyting-geometry: HeytingGeometry, 
right-angle: Rabc, 
geo-midpoint: a=m=b, 
geo-strict-between: a-b-c, 
geo-congruent: ab ≅ cd, 
geo-point: Point, 
all: ∀x:A. B[x], 
exists: ∃x:A. B[x], 
implies: P ⇒ Q, 
and: P ∧ Q
Definitions unfolded in proof : 
so_apply: x[s], 
so_lambda: λ2x.t[x], 
exists: ∃x:A. B[x], 
uiff: uiff(P;Q), 
subtract: n - m, 
cons: [a / b], 
select: L[n], 
true: True, 
squash: ↓T, 
less_than: a < b, 
not: ¬A, 
false: False, 
less_than': less_than'(a;b), 
le: A ≤ B, 
lelt: i ≤ j < k, 
int_seg: {i..j-}, 
top: Top, 
l_all: (∀x∈L.P[x]), 
geo-colinear-set: geo-colinear-set(e; L), 
cand: A c∧ B, 
and: P ∧ Q, 
uimplies: b supposing a, 
guard: {T}, 
subtype_rel: A ⊆r B, 
heyting-geometry: Error :heyting-geometry, 
uall: ∀[x:A]. B[x], 
prop: ℙ, 
member: t ∈ T, 
implies: P ⇒ Q, 
all: ∀x:A. B[x], 
geo-midpoint: a=m=b, 
rev_implies: P ⇐ Q, 
iff: P ⇐⇒ Q, 
right-angle: Rabc
Lemmas referenced : 
geo-proper-extend-exists, 
exists_wf, 
right-angle_wf, 
geo-strict-between_wf, 
geo-congruent_wf, 
geo-midpoint_wf, 
geo-length-flip, 
geo-congruent-iff-length, 
lelt_wf, 
false_wf, 
length_of_nil_lemma, 
length_of_cons_lemma, 
geo-strict-between-implies-colinear, 
geo-colinear-is-colinear-set, 
geo-strict-between-sep3, 
geo-triangle-symmetry, 
geo-triangle-colinear, 
isosceles-mid-exists, 
geo-triangle-property, 
geo-sep-sym, 
Error :basic-geo-primitives_wf, 
Error :basic-geo-structure_wf, 
basic-geometry_wf, 
Error :heyting-geometry_wf, 
subtype_rel_transitivity, 
heyting-geometry-subtype, 
basic-geometry-subtype, 
geo-point_wf, 
Error :geo-triangle_wf, 
geo-between-implies-colinear, 
midpoint-sep, 
geo-congruent_functionality, 
geo-eq_weakening, 
geo-midpoint_functionality, 
geo-midpoint-symmetry, 
symmetric-point-unicity
Rules used in proof : 
lambdaEquality, 
productEquality, 
dependent_pairFormation, 
equalitySymmetry, 
equalityTransitivity, 
baseClosed, 
imageMemberEquality, 
independent_pairFormation, 
natural_numberEquality, 
dependent_set_memberEquality, 
voidEquality, 
voidElimination, 
isect_memberEquality, 
productElimination, 
independent_functionElimination, 
dependent_functionElimination, 
because_Cache, 
sqequalRule, 
independent_isectElimination, 
instantiate, 
applyEquality, 
hypothesis, 
hypothesisEquality, 
rename, 
setElimination, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
lambdaFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}e:HeytingGeometry.  \mforall{}a,b,c:Point.
    (a  \#  bc  {}\mRightarrow{}  (\mexists{}c',b':Point.  ((c=c'=b'  \mwedge{}  ab'  \00D0  ac)  \mwedge{}  b-a-b'  \mwedge{}  a  \#  c'b'  \mwedge{}  Rac'b')))
Date html generated:
2017_10_02-PM-07_07_28
Last ObjectModification:
2017_08_08-PM-00_36_59
Theory : euclidean!plane!geometry
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