Nuprl Lemma : l_before_l_index_le

∀[T:Type]
  ∀dT:EqDecider(T). ∀L:T List. ∀x,y:T.
    ((x ∈ L) ⇒ (y ∈ L) ⇒ x before y ∈ L ∨ (x = y ∈ T) supposing index(L;x) ≤ index(L;y))


Proof




Definitions occuring in Statement :  l_index: index(L;x),  l_before: x before y ∈ l,  l_member: (x ∈ l),  list: T List,  deq: EqDecider(T),  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  le: A ≤ B,  all: ∀x:A. B[x],  implies: P ⇒ Q,  or: P ∨ Q,  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  implies: P ⇒ Q,  uimplies: b supposing a,  member: t ∈ T,  le: A ≤ B,  and: P ∧ Q,  decidable: Dec(P),  or: P ∨ Q,  subtype_rel: A ⊆r B,  int_seg: {i..j-},  prop: ℙ,  squash: ↓T,  not: ¬A,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  false: False,  top: Top,  cand: A c∧ B,  ge: i ≥ j ,  guard: {T},  nat: ℕ,  lelt: i ≤ j < k,  true: True,  iff: P ⇐⇒ Q
Lemmas referenced :  le_witness_for_triv,  decidable__lt,  istype-le,  l_index_wf,  l_member_wf,  list_wf,  deq_wf,  istype-universe,  l_before_l_index,  l_before_wf,  select_wf,  squash_wf,  le_wf,  less_than_wf,  length_wf,  istype-int,  decidable__equal_int,  full-omega-unsat,  intformand_wf,  intformnot_wf,  intformeq_wf,  itermVar_wf,  intformless_wf,  intformle_wf,  int_formula_prop_and_lemma,  istype-void,  int_formula_prop_not_lemma,  int_formula_prop_eq_lemma,  int_term_value_var_lemma,  int_formula_prop_less_lemma,  int_formula_prop_le_lemma,  int_formula_prop_wf,  non_neg_length,  decidable__le,  length_wf_nat,  int_seg_properties,  nat_properties,  itermConstant_wf,  int_term_value_constant_lemma,  equal_wf,  true_wf,  select_l_index,  subtype_rel_self,  iff_weakening_equal
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  Error :isect_memberFormation_alt,  Error :lambdaFormation_alt,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  productElimination,  equalityTransitivity,  hypothesis,  equalitySymmetry,  independent_isectElimination,  rename,  dependent_functionElimination,  because_Cache,  unionElimination,  hypothesisEquality,  applyEquality,  Error :lambdaEquality_alt,  setElimination,  Error :inhabitedIsType,  sqequalRule,  Error :universeIsType,  instantiate,  universeEquality,  Error :inlFormation_alt,  independent_functionElimination,  Error :equalityIstype,  Error :inrFormation_alt,  imageElimination,  productEquality,  natural_numberEquality,  approximateComputation,  Error :dependent_pairFormation_alt,  int_eqEquality,  Error :isect_memberEquality_alt,  voidElimination,  independent_pairFormation,  applyLambdaEquality,  imageMemberEquality,  baseClosed

Latex:
\mforall{}[T:Type]
    \mforall{}dT:EqDecider(T).  \mforall{}L:T  List.  \mforall{}x,y:T.
        ((x  \mmember{}  L)  {}\mRightarrow{}  (y  \mmember{}  L)  {}\mRightarrow{}  x  before  y  \mmember{}  L  \mvee{}  (x  =  y)  supposing  index(L;x)  \mleq{}  index(L;y))



Date html generated: 2019_06_20-PM-01_56_56
Last ObjectModification: 2019_01_13-PM-02_23_43

Theory : decidable!equality


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