Nuprl Lemma : strict-majority-property

∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[L:T List]. ∀[x:T].
  uiff(||L|| < 2 * ||filter(λy.(eq y x);L)||;strict-majority(eq;L) = (inl x) ∈ (T?))


Proof




Definitions occuring in Statement :  strict-majority: strict-majority(eq;L),  length: ||as||,  filter: filter(P;l),  list: T List,  deq: EqDecider(T),  less_than: a < b,  uiff: uiff(P;Q),  uall: ∀[x:A]. B[x],  unit: Unit,  apply: f a,  lambda: λx.A[x],  inl: inl x,  union: left + right,  multiply: n * m,  natural_number: $n,  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  prop: ℙ,  deq: EqDecider(T),  let: let,  strict-majority: strict-majority(eq;L),  uimplies: b supposing a,  and: P ∧ Q,  uiff: uiff(P;Q),  member: t ∈ T,  uall: ∀[x:A]. B[x],  exists: ∃x:A. B[x],  satisfiable_int_formula: satisfiable_int_formula(fmla),  le: A ≤ B,  ge: i ≥ j ,  eqof: eqof(d),  false: False,  not: ¬A,  rev_implies: P ⇐ Q,  iff: P ⇐⇒ Q,  so_apply: x[s],  so_lambda: λ2x.t[x],  or: P ∨ Q,  decidable: Dec(P),  all: ∀x:A. B[x],  implies: P ⇒ Q,  pi1: fst(t),  true: True,  less_than': less_than'(a;b),  subtract: n - m,  sq_stable: SqStable(P),  subtype_rel: A ⊆r B,  cand: A c∧ B,  squash: ↓T,  less_than: a < b,  nat_plus: ℕ+,  nat: ℕ,  cons: [a / b],  assert: ↑b,  bnot: ¬bb,  guard: {T},  sq_type: SQType(T),  btrue: tt,  it: ⋅,  unit: Unit,  bool: 𝔹,  exposed-bfalse: exposed-bfalse,  bfalse: ff,  ifthenelse: if b then t else f fi ,  pi2: snd(t),  no_repeats: no_repeats(T;l),  int_seg: {i..j-},  lelt: i ≤ j < k,  top: Top,  rev_uimplies: rev_uimplies(P;Q),  l_member: (x ∈ l),  nequal: a ≠ b ∈ T ,  isl: isl(x),  outl: outl(x)
Lemmas referenced :  istype-universe,  deq_wf,  list_wf,  member-less_than,  strict-majority_wf,  unit_wf2,  l_member_wf,  filter_wf5,  length_wf,  istype-less_than,  int_formula_prop_wf,  int_formula_prop_less_lemma,  int_term_value_var_lemma,  int_term_value_constant_lemma,  int_formula_prop_le_lemma,  int_formula_prop_and_lemma,  istype-int,  intformless_wf,  itermVar_wf,  itermConstant_wf,  intformle_wf,  intformand_wf,  full-omega-unsat,  non_neg_length,  length_of_nil_lemma,  istype-assert,  safe-assert-deq,  assert_wf,  not_wf,  l_all_iff,  filter_is_nil,  decidable__l_member,  decidable-equal-deq,  count-repeats_wf,  pi1_wf,  nat_plus_wf,  member-map,  member-count-repeats1,  member-count-repeats3,  le-add-cancel2,  add-zero,  add_functionality_wrt_le,  add-commutes,  add-associates,  minus-one-mul-top,  add-swap,  minus-one-mul,  minus-add,  condition-implies-le,  sq_stable__le,  not-ge-2,  istype-false,  decidable__le,  int_subtype_base,  le_wf,  set_subtype_base,  multiply-is-int-iff,  length_wf_nat,  length_of_cons_lemma,  product_subtype_list,  list-cases,  hd_wf,  equal_wf,  nil_wf,  equal-wf-T-base,  iff_weakening_uiff,  assert-bnot,  bool_subtype_base,  bool_wf,  subtype_base_sq,  bool_cases_sqequal,  eqff_to_assert,  equal-wf-base-T,  assert_of_null,  eqtt_to_assert,  null_wf,  reduce_hd_cons_lemma,  null_cons_lemma,  pi2_wf,  lt_int_wf,  filter_is_singleton,  no_repeats-count-repeats1,  no_repeats-l_member!,  map-length,  select-map,  subtype_rel_list,  top_wf,  nat_properties,  nat_plus_properties,  intformnot_wf,  int_formula_prop_not_lemma,  istype-le,  select_wf,  map_wf,  istype-top,  iff_weakening_equal,  map_select,  istype-void,  istype-nat,  int_formula_prop_eq_lemma,  int_term_value_mul_lemma,  intformeq_wf,  itermMultiply_wf,  satisfiable-full-omega-tt,  decidable__lt,  assert_of_lt_int,  eqof_wf,  less_than_wf,  decidable__equal_int,  sum-count-repeats,  and_wf,  squash_wf,  lelt_wf,  int_seg_wf,  int_seg_properties,  isolate_summand,  neg_assert_of_eq_int,  assert_of_eq_int,  eq_int_wf,  bnot_wf,  uiff_transitivity,  iff_transitivity,  assert_of_bnot,  false_wf,  sum_lower_bound,  int_term_value_add_lemma,  itermAdd_wf,  btrue_neq_bfalse,  bfalse_wf,  isl_wf,  btrue_wf,  bool_cases,  outl_wf,  equal-wf-base,  subtype_rel_product,  member_filter,  cons_member,  nat_wf
Rules used in proof :  universeEquality,  instantiate,  independent_isectElimination,  because_Cache,  isectIsTypeImplies,  axiomEquality,  isect_memberEquality_alt,  independent_pairEquality,  productElimination,  inlEquality_alt,  unionIsType,  equalityIstype,  universeIsType,  inhabitedIsType,  setIsType,  rename,  setElimination,  applyEquality,  lambdaEquality_alt,  natural_numberEquality,  multiplyEquality,  hypothesisEquality,  thin,  isectElimination,  sqequalHypSubstitution,  extract_by_obid,  hypothesis,  sqequalRule,  independent_pairFormation,  cut,  introduction,  isect_memberFormation_alt,  sqequalReflexivity,  computationStep,  sqequalTransitivity,  sqequalSubstitution,  Error :memTop,  int_eqEquality,  dependent_pairFormation_alt,  approximateComputation,  voidElimination,  applyLambdaEquality,  productIsType,  equalityTransitivity,  dependent_set_memberEquality_alt,  equalitySymmetry,  hyp_replacement,  unionElimination,  lambdaFormation_alt,  dependent_functionElimination,  independent_functionElimination,  productEquality,  minusEquality,  imageMemberEquality,  addEquality,  intEquality,  imageElimination,  hypothesis_subsumption,  cumulativity,  promote_hyp,  baseClosed,  unionEquality,  equalityElimination,  functionIsTypeImplies,  functionIsType,  computeAll,  voidEquality,  isect_memberEquality,  dependent_pairFormation,  setEquality,  lambdaEquality,  lambdaFormation,  functionEquality,  dependent_set_memberEquality,  impliesFunctionality,  inlEquality,  inlFormation

Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[L:T  List].  \mforall{}[x:T].
    uiff(||L||  <  2  *  ||filter(\mlambda{}y.(eq  y  x);L)||;strict-majority(eq;L)  =  (inl  x))



Date html generated: 2020_05_19-PM-09_52_28
Last ObjectModification: 2019_12_26-AM-11_47_50

Theory : decidable!equality


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