Nuprl Lemma : remove-repeats_property

∀[T:Type]
  ∀eq:EqDecider(T). ∀L:T List.  (no_repeats(T;remove-repeats(eq;L)) ∧ (∀a:T. ((a ∈ remove-repeats(eq;L)) ⇐⇒ (a ∈ L))))


Proof




Definitions occuring in Statement :  remove-repeats: remove-repeats(eq;L),  no_repeats: no_repeats(T;l),  l_member: (x ∈ l),  list: T List,  deq: EqDecider(T),  uall: ∀[x:A]. B[x],  all: ∀x:A. B[x],  iff: P ⇐⇒ Q,  and: P ∧ Q,  universe: Type
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,  so_apply: x[s],  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  implies: P ⇒ Q,  remove-repeats: remove-repeats(eq;L),  so_lambda: so_lambda(x,y,z.t[x; y; z]),  top: Top,  so_apply: x[s1;s2;s3],  cand: A c∧ B,  deq: EqDecider(T),  uiff: uiff(P;Q),  uimplies: b supposing a,  not: ¬A,  false: False,  eqof: eqof(d),  or: P ∨ Q,  guard: {T},  decidable: Dec(P)
Lemmas referenced :  list_induction,  no_repeats_wf,  remove-repeats_wf,  all_wf,  iff_wf,  l_member_wf,  list_wf,  list_ind_nil_lemma,  no_repeats_nil,  nil_wf,  list_ind_cons_lemma,  no_repeats_cons,  filter_wf5,  bnot_wf,  no_repeats_filter,  cons_wf,  deq_wf,  member_filter,  not_wf,  assert_wf,  member_wf,  eqof_wf,  equal_wf,  iff_transitivity,  iff_weakening_uiff,  assert_of_bnot,  safe-assert-deq,  cons_member,  decidable-equal-deq
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  lambdaFormation,  cut,  thin,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  hypothesisEquality,  sqequalRule,  lambdaEquality,  productEquality,  cumulativity,  hypothesis,  independent_functionElimination,  dependent_functionElimination,  isect_memberEquality,  voidElimination,  voidEquality,  independent_pairFormation,  because_Cache,  rename,  productElimination,  applyEquality,  setElimination,  setEquality,  independent_isectElimination,  universeEquality,  addLevel,  impliesFunctionality,  andLevelFunctionality,  levelHypothesis,  impliesLevelFunctionality,  unionElimination,  inlFormation,  inrFormation

Latex:
\mforall{}[T:Type]
    \mforall{}eq:EqDecider(T).  \mforall{}L:T  List.
        (no\_repeats(T;remove-repeats(eq;L))  \mwedge{}  (\mforall{}a:T.  ((a  \mmember{}  remove-repeats(eq;L))  \mLeftarrow{}{}\mRightarrow{}  (a  \mmember{}  L))))



Date html generated: 2017_04_17-AM-09_10_16
Last ObjectModification: 2017_02_27-PM-05_18_28

Theory : decidable!equality


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