Nuprl Lemma : Euclid-Prop16-construction-lemma

∀g:EuclideanPlane. ∀a,b,c:Point.
  (a # bc ⇒ (∃x:{x:Point| b=x=c} . ∃y:{y:Point| a=x=y} . (abc ≅a ycb ∧ (b ≠ x ∧ x ≠ c) ∧ a ≠ x ∧ x ≠ y)))


Proof




Definitions occuring in Statement :  geo-cong-angle: abc ≅a xyz,  euclidean-plane: EuclideanPlane,  geo-lsep: a # bc,  geo-midpoint: a=m=b,  geo-sep: a ≠ b,  geo-point: Point,  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  implies: P ⇒ Q,  and: P ∧ Q,  set: {x:A| B[x]} 
Definitions unfolded in proof :  all: ∀x:A. B[x],  implies: P ⇒ Q,  member: t ∈ T,  guard: {T},  and: P ∧ Q,  uall: ∀[x:A]. B[x],  subtype_rel: A ⊆r B,  prop: ℙ,  sq_exists: ∃x:A [B[x]],  euclidean-plane: EuclideanPlane,  sq_stable: SqStable(P),  squash: ↓T,  exists: ∃x:A. B[x],  cand: A c∧ B,  basic-geometry: BasicGeometry,  uimplies: b supposing a,  geo-midpoint: a=m=b,  geo-colinear-set: geo-colinear-set(e; L),  l_all: (∀x∈L.P[x]),  top: Top,  int_seg: {i..j-},  lelt: i ≤ j < k,  le: A ≤ B,  less_than': less_than'(a;b),  false: False,  not: ¬A,  less_than: a < b,  true: True,  select: L[n],  cons: [a / b],  subtract: n - m,  basic-geometry-: BasicGeometry-,  uiff: uiff(P;Q),  geo-strict-between: a-b-c,  geo-cong-angle: abc ≅a xyz
Lemmas referenced :  Euclid-midpoint,  lsep-implies-sep,  geo-sep_wf,  sq_stable__midpoint,  geo-midpoint_wf,  colinear-lsep,  lsep-all-sym,  geo-sep-sym,  midpoint-sep,  geo-colinear-permute,  geo-colinear-is-colinear-set,  geo-between-implies-colinear,  length_of_cons_lemma,  istype-void,  length_of_nil_lemma,  istype-false,  istype-le,  istype-less_than,  geo-cong-angle_wf,  geo-lsep_wf,  euclidean-plane-structure-subtype,  euclidean-plane-subtype,  subtype_rel_transitivity,  euclidean-plane_wf,  euclidean-plane-structure_wf,  geo-primitives_wf,  geo-point_wf,  colinear-implies-midpoint,  geo-strict-between-sep1,  geo-strict-between-implies-colinear,  geo-congruent-iff-length,  geo-length-flip,  geo-strict-between-sep3,  geo-proper-extend-exists,  geo-strict-between-implies-between,  geo-between-symmetry,  euclidean-plane-axioms,  geo-strict-between-sep2,  geo-between-trivial,  vertical-angles-congruent,  geo-between_wf,  geo-congruent_wf,  geo-sas2,  geo-between-out,  geo-out_weakening,  geo-eq_weakening,  out-preserves-angle-cong_1
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  lambdaFormation_alt,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  dependent_functionElimination,  thin,  hypothesisEquality,  because_Cache,  independent_functionElimination,  hypothesis,  productElimination,  dependent_set_memberEquality_alt,  universeIsType,  isectElimination,  applyEquality,  sqequalRule,  setElimination,  rename,  imageMemberEquality,  baseClosed,  imageElimination,  dependent_pairFormation_alt,  independent_isectElimination,  isect_memberEquality_alt,  voidElimination,  natural_numberEquality,  independent_pairFormation,  productIsType,  setIsType,  instantiate,  inhabitedIsType,  equalityTransitivity,  equalitySymmetry

Latex:
\mforall{}g:EuclideanPlane.  \mforall{}a,b,c:Point.
    (a  \#  bc
    {}\mRightarrow{}  (\mexists{}x:\{x:Point|  b=x=c\}  .  \mexists{}y:\{y:Point|  a=x=y\}  .  (abc  \mcong{}\msuba{}  ycb  \mwedge{}  (b  \mneq{}  x  \mwedge{}  x  \mneq{}  c)  \mwedge{}  a  \mneq{}  x  \mwedge{}  x  \mneq{}  y)))



Date html generated: 2019_10_16-PM-02_14_38
Last ObjectModification: 2018_12_03-PM-09_58_16

Theory : euclidean!plane!geometry


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