Nuprl Lemma : remove-repeats-fun-member

∀[A,B:Type].
  ∀eq:EqDecider(B). ∀f:A ⟶ B. ∀L:A List. ∀a:A.
    ((a ∈ remove-repeats-fun(eq;f;L)) ⇐⇒ ∃i:ℕ||L||. ((L[i] = a ∈ A) ∧ (∀j:ℕi. (¬((f L[j]) = (f a) ∈ B)))))


Proof




Definitions occuring in Statement :  remove-repeats-fun: remove-repeats-fun(eq;f;L),  l_member: (x ∈ l),  select: L[n],  length: ||as||,  list: T List,  deq: EqDecider(T),  int_seg: {i..j-},  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  iff: P ⇐⇒ Q,  not: ¬A,  and: P ∧ Q,  apply: f a,  function: x:A ⟶ B[x],  natural_number: $n,  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  member: t ∈ T,  so_lambda: λ2x.t[x],  prop: ℙ,  and: P ∧ Q,  int_seg: {i..j-},  uimplies: b supposing a,  guard: {T},  lelt: i ≤ j < k,  decidable: Dec(P),  or: P ∨ Q,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  false: False,  implies: P ⇒ Q,  not: ¬A,  top: Top,  less_than: a < b,  squash: ↓T,  so_apply: x[s],  remove-repeats-fun: remove-repeats-fun(eq;f;L),  so_lambda: so_lambda(x,y,z.t[x; y; z]),  so_apply: x[s1;s2;s3],  select: L[n],  nil: [],  it: ⋅,  so_lambda: λ2x y.t[x; y],  so_apply: x[s1;s2],  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  deq: EqDecider(T),  le: A ≤ B,  less_than': less_than'(a;b),  nat_plus: ℕ+,  true: True,  uiff: uiff(P;Q),  cons: [a / b],  cand: A c∧ B,  ge: i ≥ j ,  eqof: eqof(d),  subtract: n - m,  subtype_rel: A ⊆r B
Lemmas referenced :  list_induction,  all_wf,  iff_wf,  l_member_wf,  remove-repeats-fun_wf,  exists_wf,  int_seg_wf,  length_wf,  equal_wf,  select_wf,  int_seg_properties,  decidable__le,  satisfiable-full-omega-tt,  intformand_wf,  intformnot_wf,  intformle_wf,  itermConstant_wf,  itermVar_wf,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_le_lemma,  int_term_value_constant_lemma,  int_term_value_var_lemma,  int_formula_prop_wf,  decidable__lt,  intformless_wf,  int_formula_prop_less_lemma,  not_wf,  list_wf,  list_ind_nil_lemma,  length_of_nil_lemma,  stuck-spread,  base_wf,  null_nil_lemma,  btrue_wf,  member-implies-null-eq-bfalse,  nil_wf,  btrue_neq_bfalse,  equal-wf-base-T,  list_ind_cons_lemma,  length_of_cons_lemma,  cons_wf,  filter_wf5,  bnot_wf,  deq_wf,  cons_member,  false_wf,  add_nat_plus,  length_wf_nat,  less_than_wf,  nat_plus_wf,  nat_plus_properties,  add-is-int-iff,  itermAdd_wf,  intformeq_wf,  int_term_value_add_lemma,  int_formula_prop_eq_lemma,  lelt_wf,  non_neg_length,  member_filter_2,  assert_wf,  eqof_wf,  iff_transitivity,  iff_weakening_uiff,  assert_of_bnot,  safe-assert-deq,  add-member-int_seg2,  subtract_wf,  itermSubtract_wf,  int_term_value_subtract_lemma,  select-cons-tl,  add-subtract-cancel,  decidable__equal_int,  squash_wf,  le_wf,  iff_weakening_equal,  select_cons_tl,  true_wf,  member_filter
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  lambdaFormation,  cut,  thin,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  hypothesisEquality,  sqequalRule,  lambdaEquality,  cumulativity,  because_Cache,  functionExtensionality,  applyEquality,  hypothesis,  natural_numberEquality,  productEquality,  setElimination,  rename,  independent_isectElimination,  productElimination,  dependent_functionElimination,  unionElimination,  dependent_pairFormation,  int_eqEquality,  intEquality,  isect_memberEquality,  voidElimination,  voidEquality,  independent_pairFormation,  computeAll,  imageElimination,  independent_functionElimination,  baseClosed,  equalityTransitivity,  equalitySymmetry,  setEquality,  functionEquality,  universeEquality,  dependent_set_memberEquality,  imageMemberEquality,  applyLambdaEquality,  pointwiseFunctionality,  promote_hyp,  baseApply,  closedConclusion,  addEquality,  impliesFunctionality,  inlFormation,  inrFormation

Latex:
\mforall{}[A,B:Type].
    \mforall{}eq:EqDecider(B).  \mforall{}f:A  {}\mrightarrow{}  B.  \mforall{}L:A  List.  \mforall{}a:A.
        ((a  \mmember{}  remove-repeats-fun(eq;f;L))  \mLeftarrow{}{}\mRightarrow{}  \mexists{}i:\mBbbN{}||L||.  ((L[i]  =  a)  \mwedge{}  (\mforall{}j:\mBbbN{}i.  (\mneg{}((f  L[j])  =  (f  a))))))



Date html generated: 2017_04_17-AM-09_12_07
Last ObjectModification: 2017_02_27-PM-05_20_47

Theory : decidable!equality


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