Nuprl Lemma : split_tail_lemma

∀[A:Type]
  ∀f:A ⟶ 𝔹. ∀L:A List.
    (∀a∈L.∃L1,L2:A List. (((L = (L1 @ L2) ∈ (A List)) ∧ (a ∈ L2) ∧ (∀b∈L2.↑f[b])) ∧ ¬↑f[last(L1)] supposing ¬↑null(L1)) 
          supposing (∀b≥a∈L.↑f[b]))


Proof




Definitions occuring in Statement :  l_all_since: (∀x≥a∈L.P[x]),  l_all: (∀x∈L.P[x]),  last: last(L),  l_member: (x ∈ l),  null: null(as),  append: as @ bs,  list: T List,  assert: ↑b,  bool: 𝔹,  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  so_apply: x[s],  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  not: ¬A,  and: P ∧ Q,  function: x:A ⟶ B[x],  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,  uimplies: b supposing a,  so_apply: x[s],  and: P ∧ Q,  top: Top,  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  implies: P ⇒ Q,  l_all_since: (∀x≥a∈L.P[x]),  exists: ∃x:A. B[x],  cand: A c∧ B,  squash: ↓T,  true: True,  subtype_rel: A ⊆r B,  guard: {T},  not: ¬A,  false: False,  split_tail: split_tail(L | ∀x.f[x]),  so_lambda: so_lambda(x,y,z.t[x; y; z]),  so_apply: x[s1;s2;s3],  pi1: fst(t),  assert: ↑b,  ifthenelse: if b then t else f fi ,  btrue: tt,  bool: 𝔹,  unit: Unit,  it: ⋅,  uiff: uiff(P;Q),  bfalse: ff,  or: P ∨ Q,  sq_type: SQType(T),  bnot: ¬bb
Lemmas referenced :  l_all_iff,  l_member_wf,  isect_wf,  l_all_since_wf,  assert_wf,  exists_wf,  list_wf,  equal_wf,  append_wf,  length_wf,  length-append,  l_all_wf,  not_wf,  null_wf,  last_wf,  assert_witness,  l_before_wf,  bool_wf,  split_tail_wf,  pi1_wf,  pi2_wf,  squash_wf,  true_wf,  split_tail_rel,  iff_weakening_equal,  all_wf,  split_tail_max,  split_tail_correct,  l_all_fwd,  list_induction,  list_ind_nil_lemma,  null_nil_lemma,  list_ind_cons_lemma,  eqtt_to_assert,  eqff_to_assert,  bool_cases_sqequal,  subtype_base_sq,  bool_subtype_base,  assert-bnot,  list_ind_wf,  nil_wf,  cons_wf,  null_cons_lemma,  false_wf,  assert_functionality_wrt_uiff,  assert_elim,  bfalse_wf,  btrue_neq_bfalse,  last_cons,  last_singleton
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  lambdaFormation,  cut,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  dependent_functionElimination,  sqequalRule,  lambdaEquality,  cumulativity,  hypothesis,  setElimination,  rename,  applyEquality,  functionExtensionality,  because_Cache,  productEquality,  applyLambdaEquality,  isect_memberEquality,  voidElimination,  voidEquality,  setEquality,  isectEquality,  independent_isectElimination,  productElimination,  independent_functionElimination,  independent_pairEquality,  functionEquality,  universeEquality,  dependent_pairFormation,  equalityTransitivity,  equalitySymmetry,  imageElimination,  natural_numberEquality,  imageMemberEquality,  baseClosed,  independent_pairFormation,  addLevel,  existsFunctionality,  andLevelFunctionality,  existsLevelFunctionality,  unionElimination,  equalityElimination,  promote_hyp,  instantiate,  impliesFunctionality,  levelHypothesis

Latex:
\mforall{}[A:Type]
    \mforall{}f:A  {}\mrightarrow{}  \mBbbB{}.  \mforall{}L:A  List.
        (\mforall{}a\mmember{}L.\mexists{}L1,L2:A  List
                      (((L  =  (L1  @  L2))  \mwedge{}  (a  \mmember{}  L2)  \mwedge{}  (\mforall{}b\mmember{}L2.\muparrow{}f[b]))  \mwedge{}  \mneg{}\muparrow{}f[last(L1)]  supposing  \mneg{}\muparrow{}null(L1)) 
                    supposing  (\mforall{}b\mgeq{}a\mmember{}L.\muparrow{}f[b]))



Date html generated: 2017_10_01-AM-08_34_59
Last ObjectModification: 2017_07_26-PM-04_25_36

Theory : list!


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