Nuprl Lemma : not-dist-lemma-lt
∀g:EuclideanPlane. ∀a,b,c,d,e,f:Point.  ((¬D(a;b;c;d;e;f)) 
⇒ (¬|ef| < |ab| + |cd|))
Proof
Definitions occuring in Statement : 
dist: D(a;b;c;d;e;f)
, 
geo-lt: p < q
, 
geo-add-length: p + q
, 
geo-length: |s|
, 
geo-mk-seg: ab
, 
euclidean-plane: EuclideanPlane
, 
geo-point: Point
, 
all: ∀x:A. B[x]
, 
not: ¬A
, 
implies: P 
⇒ Q
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
false: False
, 
member: t ∈ T
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
uall: ∀[x:A]. B[x]
, 
basic-geometry: BasicGeometry
, 
euclidean-plane: EuclideanPlane
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
uimplies: b supposing a
Lemmas referenced : 
dist-iff-lt, 
geo-lt_wf, 
geo-length_wf, 
geo-mk-seg_wf, 
geo-add-length_wf, 
not_wf, 
dist_wf, 
geo-point_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
subtype_rel_transitivity, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
cut, 
thin, 
hypothesis, 
sqequalHypSubstitution, 
independent_functionElimination, 
introduction, 
extract_by_obid, 
dependent_functionElimination, 
hypothesisEquality, 
productElimination, 
voidElimination, 
universeIsType, 
isectElimination, 
sqequalRule, 
setElimination, 
rename, 
because_Cache, 
inhabitedIsType, 
applyEquality, 
instantiate, 
independent_isectElimination
Latex:
\mforall{}g:EuclideanPlane.  \mforall{}a,b,c,d,e,f:Point.    ((\mneg{}D(a;b;c;d;e;f))  {}\mRightarrow{}  (\mneg{}|ef|  <  |ab|  +  |cd|))
Date html generated:
2019_10_16-PM-02_51_21
Last ObjectModification:
2018_10_03-PM-00_27_25
Theory : euclidean!plane!geometry
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