Nuprl Lemma : remove-repeats-length-no-repeats

∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[L:T List].  ||remove-repeats(eq;L)|| = ||L|| ∈ ℤ supposing no_repeats(T;L)


Proof




Definitions occuring in Statement :  remove-repeats: remove-repeats(eq;L),  no_repeats: no_repeats(T;l),  length: ||as||,  list: T List,  deq: EqDecider(T),  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  int: ℤ,  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  so_lambda: λ2x.t[x],  implies: P ⇒ Q,  prop: ℙ,  so_apply: x[s],  all: ∀x:A. B[x],  uimplies: b supposing a,  top: Top,  uiff: uiff(P;Q),  and: P ∧ Q,  append: as @ bs,  so_lambda: so_lambda(x,y,z.t[x; y; z]),  so_apply: x[s1;s2;s3],  squash: ↓T,  true: True,  subtype_rel: A ⊆r B,  guard: {T},  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  or: P ∨ Q,  not: ¬A,  false: False,  decidable: Dec(P),  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x]
Lemmas referenced :  list_induction,  no_repeats_wf,  equal_wf,  length_wf,  remove-repeats_wf,  list_wf,  deq_wf,  remove_repeats_nil_lemma,  length_of_nil_lemma,  nil_wf,  no_repeats_cons,  list_ind_cons_lemma,  list_ind_nil_lemma,  squash_wf,  true_wf,  remove-repeats-append,  cons_wf,  append_wf,  iff_weakening_equal,  remove-repeats-append-one-member,  length-append,  length_of_cons_lemma,  decidable__equal_int,  satisfiable-full-omega-tt,  intformand_wf,  intformnot_wf,  intformeq_wf,  itermVar_wf,  itermAdd_wf,  itermConstant_wf,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_eq_lemma,  int_term_value_var_lemma,  int_term_value_add_lemma,  int_term_value_constant_lemma,  int_formula_prop_wf
Rules used in proof :  cut,  thin,  introduction,  extract_by_obid,  sqequalHypSubstitution,  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isectElimination,  hypothesisEquality,  sqequalRule,  lambdaEquality,  functionEquality,  cumulativity,  hypothesis,  intEquality,  independent_functionElimination,  lambdaFormation,  rename,  because_Cache,  dependent_functionElimination,  universeEquality,  isect_memberFormation,  isect_memberEquality,  axiomEquality,  equalityTransitivity,  equalitySymmetry,  voidElimination,  voidEquality,  natural_numberEquality,  productElimination,  independent_isectElimination,  applyEquality,  imageElimination,  equalityUniverse,  levelHypothesis,  imageMemberEquality,  baseClosed,  unionElimination,  dependent_pairFormation,  int_eqEquality,  independent_pairFormation,  computeAll

Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[L:T  List].
    ||remove-repeats(eq;L)||  =  ||L||  supposing  no\_repeats(T;L)



Date html generated: 2017_04_17-AM-09_12_42
Last ObjectModification: 2017_02_27-PM-05_19_39

Theory : decidable!equality


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