Nuprl Lemma : eu-segments-cross

e:EuclideanPlane. ∀p,b,q,a:Point.  ((∃c:Point. ((¬Colinear(a;b;c)) ∧ a-p-c ∧ b_q_c))  (∃x:Point. (p-x-b ∧ q-x-a)))


Proof




Definitions occuring in Statement :  euclidean-plane: EuclideanPlane eu-between-eq: a_b_c eu-colinear: Colinear(a;b;c) eu-between: a-b-c eu-point: Point all: x:A. B[x] exists: x:A. B[x] not: ¬A implies:  Q and: P ∧ Q
Definitions unfolded in proof :  all: x:A. B[x] implies:  Q exists: x:A. B[x] and: P ∧ Q member: t ∈ T uall: [x:A]. B[x] euclidean-plane: EuclideanPlane prop: cand: c∧ B so_lambda: λ2x.t[x] so_apply: x[s]
Lemmas referenced :  eu-inner-pasch-property not_wf eu-colinear_wf eu-between_wf eu-between-eq_wf eu-inner-pasch_wf and_wf exists_wf eu-point_wf euclidean-plane_wf
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity lambdaFormation sqequalHypSubstitution productElimination thin cut lemma_by_obid dependent_functionElimination hypothesisEquality isectElimination dependent_set_memberEquality because_Cache hypothesis setElimination rename dependent_pairFormation independent_pairFormation sqequalRule lambdaEquality

Latex:
\mforall{}e:EuclideanPlane.  \mforall{}p,b,q,a:Point.
    ((\mexists{}c:Point.  ((\mneg{}Colinear(a;b;c))  \mwedge{}  a-p-c  \mwedge{}  b\_q\_c))  {}\mRightarrow{}  (\mexists{}x:Point.  (p-x-b  \mwedge{}  q-x-a)))



Date html generated: 2016_05_18-AM-06_33_43
Last ObjectModification: 2015_12_28-AM-09_27_47

Theory : euclidean!geometry


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