Nuprl Lemma : in-hull-next2

∀g:OrientedPlane. ∀xs:{xs:Point List| geo-general-position(g;xs)} . ∀i,j:ℕ||xs||.
  ((¬(i = j ∈ ℤ)) ⇒ (ij ∈ Hull(xs) ∧ 2 < ||xs||) ⇒ (∃k:ℕ||xs||. (((¬(k = i ∈ ℤ)) ∧ (¬(k = j ∈ ℤ))) ∧ ki ∈ Hull(xs))))


Proof




Definitions occuring in Statement :  in-hull: ij ∈ Hull(xs),  geo-general-position: geo-general-position(g;xs),  oriented-plane: OrientedPlane,  geo-point: Point,  length: ||as||,  list: T List,  int_seg: {i..j-},  less_than: a < b,  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  not: ¬A,  implies: P ⇒ Q,  and: P ∧ Q,  set: {x:A| B[x]} ,  natural_number: $n,  int: ℤ,  equal: s = t ∈ T
Definitions unfolded in proof :  so_apply: x[s],  so_lambda: λ2x.t[x],  top: Top,  satisfiable_int_formula: satisfiable_int_formula(fmla),  false: False,  not: ¬A,  prop: ℙ,  uimplies: b supposing a,  guard: {T},  cand: A c∧ B,  lelt: i ≤ j < k,  subtype_rel: A ⊆r B,  uall: ∀[x:A]. B[x],  int_seg: {i..j-},  exists: ∃x:A. B[x],  member: t ∈ T,  and: P ∧ Q,  implies: P ⇒ Q,  all: ∀x:A. B[x],  in-hull: ij ∈ Hull(xs),  or: P ∨ Q,  decidable: Dec(P),  sq_type: SQType(T),  rev_uimplies: rev_uimplies(P;Q),  uiff: uiff(P;Q)
Lemmas referenced :  list_wf,  set_wf,  int_seg_wf,  less_than_wf,  geo-general-position_wf,  in-hull_wf,  not_wf,  equal_wf,  int_formula_prop_wf,  int_formula_prop_not_lemma,  int_term_value_var_lemma,  int_formula_prop_eq_lemma,  int_formula_prop_and_lemma,  intformnot_wf,  itermVar_wf,  intformeq_wf,  intformand_wf,  full-omega-unsat,  int_seg_properties,  geo-primitives_wf,  euclidean-plane-structure_wf,  euclidean-plane_wf,  oriented-plane_wf,  subtype_rel_transitivity,  oriented-plane-subtype,  euclidean-plane-subtype,  euclidean-plane-structure-subtype,  geo-point_wf,  length_wf,  lelt_wf,  in-hull-leftmost,  decidable__equal_int,  int_subtype_base,  subtype_base_sq,  left-test-symmetry,  left-test_wf,  assert_functionality_wrt_uiff
Rules used in proof :  productEquality,  voidEquality,  voidElimination,  isect_memberEquality,  intEquality,  int_eqEquality,  lambdaEquality,  approximateComputation,  independent_pairFormation,  because_Cache,  sqequalRule,  independent_isectElimination,  instantiate,  applyEquality,  natural_numberEquality,  isectElimination,  dependent_set_memberEquality,  rename,  setElimination,  dependent_pairFormation,  hypothesis,  independent_functionElimination,  hypothesisEquality,  dependent_functionElimination,  extract_by_obid,  introduction,  cut,  thin,  productElimination,  sqequalHypSubstitution,  lambdaFormation,  sqequalReflexivity,  computationStep,  sqequalTransitivity,  sqequalSubstitution,  unionElimination,  equalitySymmetry,  equalityTransitivity,  cumulativity

Latex:
\mforall{}g:OrientedPlane.  \mforall{}xs:\{xs:Point  List|  geo-general-position(g;xs)\}  .  \mforall{}i,j:\mBbbN{}||xs||.
    ((\mneg{}(i  =  j))
    {}\mRightarrow{}  (ij  \mmember{}  Hull(xs)  \mwedge{}  2  <  ||xs||)
    {}\mRightarrow{}  (\mexists{}k:\mBbbN{}||xs||.  (((\mneg{}(k  =  i))  \mwedge{}  (\mneg{}(k  =  j)))  \mwedge{}  ki  \mmember{}  Hull(xs))))



Date html generated: 2018_05_22-PM-00_07_27
Last ObjectModification: 2017_12_12-PM-04_23_39

Theory : euclidean!plane!geometry


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