Nuprl Lemma : dist-lemma-lt2

∀g:EuclideanPlane. ∀a,b,c,d,e,f:Point.  (|ef| < |ab| + |cd| ⇒ D(a;b;c;d;e;f))


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],  implies: P ⇒ Q
Definitions unfolded in proof :  all: ∀x:A. B[x],  implies: P ⇒ Q,  dist: D(a;b;c;d;e;f),  exists: ∃x:A. B[x],  member: t ∈ T,  euclidean-plane: EuclideanPlane,  uall: ∀[x:A]. B[x],  basic-geometry: BasicGeometry,  subtype_rel: A ⊆r B,  and: P ∧ Q,  cand: A c∧ B,  guard: {T},  uimplies: b supposing a,  prop: ℙ,  iff: P ⇐⇒ Q
Lemmas referenced :  geo-X_wf,  geo-length_wf1,  geo-mk-seg_wf,  geo-add-length_wf1,  geo-add-length-property1,  geo-length-property,  geo-add-length-property2,  geo-between_wf,  euclidean-plane-structure-subtype,  euclidean-plane-subtype,  subtype_rel_transitivity,  euclidean-plane_wf,  euclidean-plane-structure_wf,  geo-primitives_wf,  geo-congruent_wf,  geo-sep_wf,  geo-lt_wf,  geo-length_wf,  geo-add-length_wf,  geo-point_wf,  geo-lt-iff-strict-between-points,  geo-sep-sym,  geo-le-iff-between-points
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation_alt,  dependent_pairFormation_alt,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  dependent_functionElimination,  thin,  setElimination,  rename,  because_Cache,  hypothesis,  isectElimination,  sqequalRule,  hypothesisEquality,  applyEquality,  lambdaEquality_alt,  inhabitedIsType,  equalityTransitivity,  equalitySymmetry,  independent_pairFormation,  productIsType,  universeIsType,  instantiate,  independent_isectElimination,  setIsType,  productElimination,  independent_functionElimination,  dependent_set_memberEquality_alt

Latex:
\mforall{}g:EuclideanPlane.  \mforall{}a,b,c,d,e,f:Point.    (|ef|  <  |ab|  +  |cd|  {}\mRightarrow{}  D(a;b;c;d;e;f))



Date html generated: 2019_10_16-PM-02_50_44
Last ObjectModification: 2018_10_03-AM-11_23_23

Theory : euclidean!plane!geometry


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