Nuprl Lemma : lsep-opposite-iff

g:OrientedPlane. ∀a,b,x,y:Point.
  (x ab  ab  (∃z:Point. (x_z_y ∧ Colinear(z;a;b)) ⇐⇒ leftof ab ⇐⇒ leftof ba))


Proof




Definitions occuring in Statement :  oriented-plane: OrientedPlane geo-lsep: bc geo-colinear: Colinear(a;b;c) geo-left: leftof bc geo-between: a_b_c geo-point: Point all: x:A. B[x] exists: x:A. B[x] iff: ⇐⇒ Q implies:  Q and: P ∧ Q
Definitions unfolded in proof :  so_apply: x[s] so_lambda: λ2x.t[x] uimplies: supposing a guard: {T} subtype_rel: A ⊆B false: False not: ¬A rev_implies:  Q oriented-plane: Error :oriented-plane,  uall: [x:A]. B[x] prop: member: t ∈ T or: P ∨ Q geo-lsep: bc exists: x:A. B[x] and: P ∧ Q iff: ⇐⇒ Q implies:  Q all: x:A. B[x] cand: c∧ B euclidean-geometry: Error :euclidean-geometry
Lemmas referenced :  geo-lsep_wf iff_wf geo-colinear_wf geo-between_wf Error :basic-geo-primitives_wf,  Error :basic-geo-structure_wf,  basic-geometry-_wf Error :oriented-plane_wf,  subtype_rel_transitivity Error :oriented-plane-subtype,  basic-geometry--subtype geo-point_wf exists_wf not-left-and-right geo-left_wf left-between-weak Error :use-plane-sep,  lsep-symmetry lsep-symmetry2 Error :euclidean-geometry_wf,  subtype_rel_self
Rules used in proof :  productEquality lambdaEquality sqequalRule independent_isectElimination instantiate applyEquality voidElimination independent_functionElimination dependent_functionElimination hypothesisEquality hypothesis because_Cache rename setElimination isectElimination extract_by_obid introduction cut unionElimination thin productElimination sqequalHypSubstitution independent_pairFormation lambdaFormation sqequalReflexivity computationStep sqequalTransitivity sqequalSubstitution inlFormation inrFormation dependent_pairFormation

Latex:
\mforall{}g:OrientedPlane.  \mforall{}a,b,x,y:Point.
    (x  \#  ab  {}\mRightarrow{}  y  \#  ab  {}\mRightarrow{}  (\mexists{}z:Point.  (x\_z\_y  \mwedge{}  Colinear(z;a;b))  \mLeftarrow{}{}\mRightarrow{}  x  leftof  ab  \mLeftarrow{}{}\mRightarrow{}  y  leftof  ba))



Date html generated: 2017_10_02-PM-04_47_39
Last ObjectModification: 2017_08_05-AM-10_20_20

Theory : euclidean!plane!geometry


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