Nuprl Lemma : geo-gt-implies-point
∀e:EuclideanPlane. ∀a,b,c,d:Point.  (ab > cd 
⇒ c ≠ d 
⇒ (¬¬(∃f:Point. (c-d-f ∧ cf ≅ ab))))
Proof
Definitions occuring in Statement : 
euclidean-plane: EuclideanPlane
, 
geo-strict-between: a-b-c
, 
geo-gt: cd > ab
, 
geo-congruent: ab ≅ cd
, 
geo-sep: a ≠ b
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
false: False
, 
geo-gt: cd > ab
, 
squash: ↓T
, 
exists: ∃x:A. B[x]
, 
and: P ∧ Q
, 
member: t ∈ T
, 
basic-geometry: BasicGeometry
, 
euclidean-plane: EuclideanPlane
, 
subtype_rel: A ⊆r B
, 
uall: ∀[x:A]. B[x]
, 
guard: {T}
, 
uimplies: b supposing a
, 
basic-geometry-: BasicGeometry-
, 
uiff: uiff(P;Q)
, 
cand: A c∧ B
, 
prop: ℙ
, 
true: True
Lemmas referenced : 
geo-proper-extend-exists, 
geo-O_wf, 
geo-X_wf, 
geo-sep-sym, 
geo-sep-O-X, 
geo-strict-between-sep3, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
subtype_rel_transitivity, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-congruent-sep, 
geo-construction-unicity, 
geo-between-symmetry, 
geo-strict-between-implies-between, 
geo-congruent-iff-length, 
geo-eq_inversion, 
geo-add-length-between, 
geo-add-length_wf, 
squash_wf, 
true_wf, 
geo-length-type_wf, 
basic-geometry_wf, 
geo-strict-between_wf, 
geo-congruent_wf, 
istype-void, 
geo-sep_wf, 
geo-gt_wf, 
geo-point_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
thin, 
sqequalHypSubstitution, 
imageElimination, 
productElimination, 
introduction, 
extract_by_obid, 
dependent_functionElimination, 
sqequalRule, 
hypothesisEquality, 
setElimination, 
rename, 
hypothesis, 
because_Cache, 
independent_functionElimination, 
applyEquality, 
instantiate, 
isectElimination, 
independent_isectElimination, 
equalityTransitivity, 
dependent_pairFormation_alt, 
independent_pairFormation, 
lambdaEquality_alt, 
equalitySymmetry, 
universeIsType, 
inhabitedIsType, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
productIsType, 
voidElimination, 
functionIsType
Latex:
\mforall{}e:EuclideanPlane.  \mforall{}a,b,c,d:Point.    (ab  >  cd  {}\mRightarrow{}  c  \mneq{}  d  {}\mRightarrow{}  (\mneg{}\mneg{}(\mexists{}f:Point.  (c-d-f  \mwedge{}  cf  \mcong{}  ab))))
Date html generated:
2019_10_16-PM-01_17_14
Last ObjectModification:
2019_08_07-PM-02_43_56
Theory : euclidean!plane!geometry
Home
Index