Nuprl Lemma : select-front-as-reduce

[n:ℕ]. ∀[L:Top List].
  L[n] hd(reduce(λu,x. if ||x|| <then [u] else tl(x) [u] fi ;[];L)) supposing n < ||L||


Proof




Definitions occuring in Statement :  select: L[n] hd: hd(l) length: ||as|| append: as bs reduce: reduce(f;k;as) tl: tl(l) cons: [a b] nil: [] list: List nat: ifthenelse: if then else fi  lt_int: i <j less_than: a < b uimplies: supposing a uall: [x:A]. B[x] top: Top lambda: λx.A[x] add: m natural_number: $n sqequal: t
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T all: x:A. B[x] nat: implies:  Q false: False ge: i ≥  uimplies: supposing a satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] not: ¬A top: Top and: P ∧ Q prop: subtype_rel: A ⊆B guard: {T} or: P ∨ Q firstn: firstn(n;as) so_lambda: so_lambda(x,y,z.t[x; y; z]) so_apply: x[s1;s2;s3] cons: [a b] colength: colength(L) so_lambda: λ2y.t[x; y] so_apply: x[s1;s2] decidable: Dec(P) nil: [] it: so_lambda: λ2x.t[x] so_apply: x[s] sq_type: SQType(T) less_than: a < b squash: T less_than': less_than'(a;b) bool: 𝔹 unit: Unit btrue: tt uiff: uiff(P;Q) bfalse: ff bnot: ¬bb ifthenelse: if then else fi  assert: b le: A ≤ B int_seg: {i..j-} lelt: i ≤ j < k last: last(L) int_iseg: {i...j} cand: c∧ B append: as bs
Lemmas referenced :  nat_properties satisfiable-full-omega-tt 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 equal-wf-T-base nat_wf colength_wf_list top_wf less_than_transitivity1 less_than_irreflexivity list-cases reduce_nil_lemma list_ind_nil_lemma reverse_nil_lemma product_subtype_list 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 int_subtype_base decidable__equal_int reduce_cons_lemma list_wf length_wf le_int_wf bool_wf eqtt_to_assert assert_of_le_int length-reverse eqff_to_assert bool_cases_sqequal bool_subtype_base assert-bnot lt_int_wf firstn_wf assert_wf bnot_wf uiff_transitivity assert_of_lt_int assert_functionality_wrt_uiff bnot_of_lt_int cons_wf length_of_cons_lemma non_neg_length reverse-cons list_ind_cons_lemma append_firstn_lastn_sq decidable__lt lelt_wf reverse-append nth_tl_wf nth_tl_decomp length_nth_tl length_of_nil_lemma equal-wf-base reduce_tl_cons_lemma add-subtract-cancel length_firstn firstn_decomp nil_wf reduce_hd_cons_lemma hd-reverse
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation introduction cut lambdaFormation thin extract_by_obid sqequalHypSubstitution isectElimination hypothesisEquality hypothesis setElimination rename intWeakElimination natural_numberEquality independent_isectElimination dependent_pairFormation lambdaEquality int_eqEquality intEquality dependent_functionElimination isect_memberEquality voidElimination voidEquality sqequalRule independent_pairFormation computeAll independent_functionElimination sqequalAxiom applyEquality because_Cache unionElimination promote_hyp hypothesis_subsumption productElimination equalityTransitivity equalitySymmetry applyLambdaEquality dependent_set_memberEquality addEquality baseClosed instantiate cumulativity imageElimination equalityElimination productEquality

Latex:
\mforall{}[n:\mBbbN{}].  \mforall{}[L:Top  List].
    L[n]  \msim{}  hd(reduce(\mlambda{}u,x.  if  ||x||  <z  n  +  1  then  x  @  [u]  else  tl(x)  @  [u]  fi  ;[];L))  supposing  n  <  ||\000CL||



Date html generated: 2018_05_21-PM-07_35_29
Last ObjectModification: 2017_07_26-PM-05_09_38

Theory : general


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