Nuprl Lemma : decidable__exists_iseg

∀[T:Type]. ∀[P:(T List) ⟶ ℙ].  ((∀L:T List. Dec(P[L])) ⇒ (∀L:T List. Dec(∃L':T List. (L' ≤ L ∧ P[L']))))


Proof




Definitions occuring in Statement :  iseg: l1 ≤ l2,  list: T List,  decidable: Dec(P),  uall: ∀[x:A]. B[x],  prop: ℙ,  so_apply: x[s],  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  implies: P ⇒ Q,  and: P ∧ Q,  function: x:A ⟶ B[x],  universe: Type
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  implies: P ⇒ Q,  all: ∀x:A. B[x],  member: t ∈ T,  int_seg: {i..j-},  lelt: i ≤ j < k,  and: P ∧ Q,  le: A ≤ B,  uimplies: b supposing a,  not: ¬A,  satisfiable_int_formula: satisfiable_int_formula(fmla),  exists: ∃x:A. B[x],  false: False,  prop: ℙ,  decidable: Dec(P),  or: P ∨ Q,  subtype_rel: A ⊆r B,  so_lambda: λ2x.t[x],  so_apply: x[s],  guard: {T},  sq_type: SQType(T),  nat: ℕ,  ge: i ≥ j ,  less_than: a < b,  squash: ↓T,  cons: [a / b],  assert: ↑b,  ifthenelse: if b then t else f fi ,  bfalse: ff,  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  uiff: uiff(P;Q),  int_iseg: {i...j},  cand: A c∧ B,  btrue: tt,  iseg: l1 ≤ l2,  less_than': less_than'(a;b),  true: True,  last: last(L),  subtract: n - m,  length: ||as||,  list_ind: list_ind,  nil: [],  it: ⋅
Lemmas referenced :  int_seg_properties,  full-omega-unsat,  intformand_wf,  intformless_wf,  itermVar_wf,  itermConstant_wf,  intformle_wf,  istype-int,  int_formula_prop_and_lemma,  int_formula_prop_less_lemma,  int_term_value_var_lemma,  int_term_value_constant_lemma,  int_formula_prop_le_lemma,  int_formula_prop_wf,  int_seg_wf,  decidable__equal_int,  subtract_wf,  subtype_base_sq,  set_subtype_base,  lelt_wf,  int_subtype_base,  intformnot_wf,  intformeq_wf,  itermSubtract_wf,  int_formula_prop_not_lemma,  int_formula_prop_eq_lemma,  int_term_value_subtract_lemma,  decidable__le,  decidable__lt,  istype-le,  istype-less_than,  subtype_rel_self,  non_neg_length,  nat_properties,  length_wf,  decidable__assert,  null_wf,  list-cases,  product_subtype_list,  null_cons_lemma,  last-lemma-sq,  pos_length,  iff_transitivity,  not_wf,  equal-wf-T-base,  list_wf,  assert_wf,  bnot_wf,  iff_weakening_uiff,  assert_of_null,  istype-assert,  nil_wf,  length_of_nil_lemma,  istype-void,  assert_of_bnot,  firstn_wf,  length_firstn,  le_wf,  decidable_wf,  iseg_wf,  primrec-wf2,  itermAdd_wf,  int_term_value_add_lemma,  istype-nat,  length_wf_nat,  istype-universe,  iseg_weakening,  null_nil_lemma,  iseg_nil,  last_wf,  cons_wf,  append_wf,  iseg_append,  append_back_nil,  iseg_append_iff,  iseg_single,  length_of_cons_lemma,  equal_wf,  list_extensionality,  length-append,  select_wf,  squash_wf,  true_wf,  select_append_front,  select_firstn,  iff_weakening_equal,  length_firstn_eq,  less_than_wf,  add_functionality_wrt_eq,  select_append_back,  nat_wf,  select-nthtl,  subtype_rel_list,  top_wf,  nth_tl_decomp,  nth_tl_is_nil,  minus-add,  minus-minus,  add-associates,  minus-one-mul,  add-swap,  add-mul-special,  add-commutes,  zero-add,  zero-mul,  select0,  hd_wf,  istype-false
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation_alt,  lambdaFormation_alt,  cut,  thin,  introduction,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  setElimination,  rename,  productElimination,  hypothesis,  hypothesisEquality,  natural_numberEquality,  independent_isectElimination,  approximateComputation,  independent_functionElimination,  dependent_pairFormation_alt,  lambdaEquality_alt,  int_eqEquality,  dependent_functionElimination,  Error :memTop,  sqequalRule,  independent_pairFormation,  universeIsType,  voidElimination,  unionElimination,  applyEquality,  instantiate,  cumulativity,  intEquality,  inhabitedIsType,  equalityTransitivity,  equalitySymmetry,  applyLambdaEquality,  dependent_set_memberEquality_alt,  because_Cache,  productIsType,  promote_hyp,  hypothesis_subsumption,  imageElimination,  baseClosed,  functionIsType,  equalityIstype,  functionEquality,  productEquality,  setIsType,  addEquality,  universeEquality,  inrFormation_alt,  inlFormation_alt,  hyp_replacement,  imageMemberEquality,  multiplyEquality

Latex:
\mforall{}[T:Type].  \mforall{}[P:(T  List)  {}\mrightarrow{}  \mBbbP{}].
    ((\mforall{}L:T  List.  Dec(P[L]))  {}\mRightarrow{}  (\mforall{}L:T  List.  Dec(\mexists{}L':T  List.  (L'  \mleq{}  L  \mwedge{}  P[L']))))



Date html generated: 2020_05_19-PM-09_48_58
Last ObjectModification: 2019_12_31-PM-00_13_48

Theory : list_1


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