Nuprl Lemma : combine-list-as-reduce

∀[A:Type]. ∀[f:A ⟶ A ⟶ A].
  (∀[L:A List]
     combine-list(x,y.f[x;y];L) = outl(reduce(λx,y. case y of inl(z) => inl f[x;z] | inr(z) => inl x;inr ⋅ ;L)) ∈ A 
     supposing 0 < ||L||) supposing 
     (Comm(A;λx,y. f[x;y]) and 
     Assoc(A;λx,y. f[x;y]))


Proof




Definitions occuring in Statement :  combine-list: combine-list(x,y.f[x; y];L),  length: ||as||,  reduce: reduce(f;k;as),  list: T List,  comm: Comm(T;op),  assoc: Assoc(T;op),  outl: outl(x),  less_than: a < b,  it: ⋅,  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  so_apply: x[s1;s2],  lambda: λx.A[x],  function: x:A ⟶ B[x],  decide: case b of inl(x) => s[x] | inr(y) => t[y],  inr: inr x ,  inl: inl x,  natural_number: $n,  universe: Type,  equal: s = t ∈ T
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  uimplies: b supposing a,  all: ∀x:A. B[x],  or: P ∨ Q,  assert: ↑b,  ifthenelse: if b then t else f fi ,  btrue: tt,  less_than: a < b,  squash: ↓T,  less_than': less_than'(a;b),  false: False,  and: P ∧ Q,  cons: [a / b],  top: Top,  bfalse: ff,  not: ¬A,  implies: P ⇒ Q,  prop: ℙ,  exists: ∃x:A. B[x],  nat: ℕ,  ge: i ≥ j ,  satisfiable_int_formula: satisfiable_int_formula(fmla),  subtype_rel: A ⊆r B,  isl: isl(x),  colength: colength(L),  so_lambda: λ2x y.t[x; y],  so_apply: x[s1;s2],  guard: {T},  decidable: Dec(P),  nil: [],  it: ⋅,  so_lambda: λ2x.t[x],  so_apply: x[s],  sq_type: SQType(T),  nat_plus: ℕ+,  true: True,  uiff: uiff(P;Q),  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  append: as @ bs,  so_lambda: so_lambda(x,y,z.t[x; y; z]),  so_apply: x[s1;s2;s3],  outl: outl(x),  le: A ≤ B,  combine-list: combine-list(x,y.f[x; y];L),  comm: Comm(T;op),  infix_ap: x f y
Lemmas referenced :  last_lemma,  list-cases,  null_nil_lemma,  length_of_nil_lemma,  product_subtype_list,  null_cons_lemma,  length_of_cons_lemma,  false_wf,  nat_properties,  full-omega-unsat,  intformand_wf,  intformle_wf,  itermConstant_wf,  itermVar_wf,  intformless_wf,  int_formula_prop_and_lemma,  int_formula_prop_le_lemma,  int_term_value_constant_lemma,  int_term_value_var_lemma,  int_formula_prop_less_lemma,  int_formula_prop_wf,  ge_wf,  less_than_wf,  length_wf,  equal-wf-T-base,  nat_wf,  colength_wf_list,  int_subtype_base,  reduce_nil_lemma,  spread_cons_lemma,  intformeq_wf,  itermAdd_wf,  int_formula_prop_eq_lemma,  int_term_value_add_lemma,  decidable__le,  intformnot_wf,  int_formula_prop_not_lemma,  le_wf,  equal_wf,  subtract_wf,  itermSubtract_wf,  int_term_value_subtract_lemma,  subtype_base_sq,  set_subtype_base,  decidable__equal_int,  reduce_cons_lemma,  bool_wf,  bool_subtype_base,  reduce_wf,  unit_wf2,  it_wf,  btrue_wf,  list_wf,  comm_wf,  assoc_wf,  last_wf,  append_wf,  cons_wf,  nil_wf,  length-append,  add_nat_plus,  length_wf_nat,  nat_plus_wf,  nat_plus_properties,  decidable__lt,  add-is-int-iff,  outl_wf,  assert_of_tt,  squash_wf,  true_wf,  combine-list-append,  subtype_rel_self,  iff_weakening_equal,  list_ind_cons_lemma,  list_ind_nil_lemma,  combine-list_wf,  non_neg_length,  assert_wf,  isl_wf,  list_induction,  reduce_hd_cons_lemma,  reduce_tl_cons_lemma,  list_accum_nil_lemma,  list_accum_cons_lemma,  list_accum_wf,  combine-list-cons,  and_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  dependent_functionElimination,  independent_isectElimination,  hypothesis,  unionElimination,  sqequalRule,  imageElimination,  productElimination,  voidElimination,  promote_hyp,  hypothesis_subsumption,  isect_memberEquality,  voidEquality,  lambdaFormation,  setElimination,  rename,  intWeakElimination,  natural_numberEquality,  approximateComputation,  independent_functionElimination,  dependent_pairFormation,  lambdaEquality,  int_eqEquality,  intEquality,  independent_pairFormation,  axiomSqEquality,  applyEquality,  because_Cache,  equalityTransitivity,  equalitySymmetry,  applyLambdaEquality,  dependent_set_memberEquality,  addEquality,  baseClosed,  instantiate,  cumulativity,  unionEquality,  inlEquality,  inrEquality,  axiomEquality,  functionEquality,  universeEquality,  hyp_replacement,  imageMemberEquality,  pointwiseFunctionality,  baseApply,  closedConclusion,  functionExtensionality

Latex:
\mforall{}[A:Type].  \mforall{}[f:A  {}\mrightarrow{}  A  {}\mrightarrow{}  A].
    (\mforall{}[L:A  List]
          combine-list(x,y.f[x;y];L)
          =  outl(reduce(\mlambda{}x,y.  case  y  of  inl(z)  =>  inl  f[x;z]  |  inr(z)  =>  inl  x;inr  \mcdot{}  ;L)) 
          supposing  0  <  ||L||)  supposing 
          (Comm(A;\mlambda{}x,y.  f[x;y])  and 
          Assoc(A;\mlambda{}x,y.  f[x;y]))



Date html generated: 2019_06_20-PM-01_30_30
Last ObjectModification: 2018_08_21-PM-01_55_59

Theory : list_1


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