Nuprl Lemma : simple_fan_theorem

∀[X:n:ℕ ⟶ (ℕn ⟶ 𝔹) ⟶ ℙ]
  (∀n:ℕ. ∀s:ℕn ⟶ 𝔹.  Dec(X[n;s])) ⇒ (∃k:ℕ [(∀f:ℕ ⟶ 𝔹. ∃n:ℕk. X[n;f])]) supposing ∀f:ℕ ⟶ 𝔹. (↓∃n:ℕ. X[n;f])


Proof




Definitions occuring in Statement :  int_seg: {i..j-},  nat: ℕ,  bool: 𝔹,  decidable: Dec(P),  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  prop: ℙ,  so_apply: x[s1;s2],  all: ∀x:A. B[x],  sq_exists: ∃x:A [B[x]],  exists: ∃x:A. B[x],  squash: ↓T,  implies: P ⇒ Q,  function: x:A ⟶ B[x],  natural_number: $n
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  uimplies: b supposing a,  member: t ∈ T,  all: ∀x:A. B[x],  squash: ↓T,  implies: P ⇒ Q,  so_lambda: λ2x y.t[x; y],  so_lambda: λ2x.t[x],  nat: ℕ,  so_apply: x[s1;s2],  int_seg: {i..j-},  guard: {T},  sq_stable: SqStable(P),  lelt: i ≤ j < k,  and: P ∧ Q,  prop: ℙ,  subtype_rel: A ⊆r B,  le: A ≤ B,  less_than': less_than'(a;b),  false: False,  not: ¬A,  so_apply: x[s],  decidable: Dec(P),  or: P ∨ Q,  iff: P ⇐⇒ Q,  rev_implies: P ⇐ Q,  uiff: uiff(P;Q),  subtract: n - m,  top: Top,  true: True,  sq_exists: ∃x:A [B[x]],  exists: ∃x:A. B[x],  less_than: a < b,  seq-append: seq-append(n;m;s1;s2),  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  bfalse: ff,  sq_type: SQType(T),  bnot: ¬bb,  ifthenelse: if b then t else f fi ,  assert: ↑b,  ge: i ≥ j ,  nat_plus: ℕ+,  seq-adjoin: s++t
Lemmas referenced :  nat_wf,  bool_wf,  basic_bar_induction,  sq_exists_wf,  all_wf,  exists_wf,  int_seg_wf,  add_nat_wf,  sq_stable__le,  equal_wf,  le_wf,  seq-append_wf,  int_seg_subtype_nat,  false_wf,  subtype_rel_function,  subtype_rel_self,  decidable__le,  not-le-2,  condition-implies-le,  minus-add,  minus-one-mul,  zero-add,  minus-one-mul-top,  add-associates,  add-swap,  add-commutes,  add_functionality_wrt_le,  add-zero,  le-add-cancel,  seq-adjoin_wf,  decidable_wf,  squash_wf,  and_wf,  less_than_wf,  lt_int_wf,  eqtt_to_assert,  assert_of_lt_int,  top_wf,  eqff_to_assert,  bool_cases_sqequal,  subtype_base_sq,  bool_subtype_base,  assert-bnot,  not-lt-2,  less-iff-le,  btrue_wf,  set_wf,  set-value-type,  int-value-type,  bfalse_wf,  add-member-int_seg2,  subtract_wf,  le-add-cancel2,  decidable__lt,  minus-minus,  sq_stable__and,  sq_stable__less_than,  member-less_than,  le_reflexive,  one-mul,  add-mul-special,  two-mul,  mul-distributes-right,  zero-mul,  minus-zero,  omega-shadow,  mul-distributes,  mul-commutes,  mul-associates,  mul-swap,  nat_properties,  int_subtype_base,  iff_imp_equal_bool,  assert_wf,  true_wf,  not-less-implies-equal,  le-add-cancel-alt,  set_subtype_base,  decidable__int_equal,  not-equal-2,  less_than_transitivity1,  less_than_irreflexivity
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  cut,  introduction,  sqequalRule,  sqequalHypSubstitution,  lambdaEquality,  dependent_functionElimination,  thin,  hypothesisEquality,  imageElimination,  hypothesis,  imageMemberEquality,  baseClosed,  functionEquality,  extract_by_obid,  rename,  lambdaFormation,  isectElimination,  because_Cache,  natural_numberEquality,  setElimination,  applyEquality,  functionExtensionality,  dependent_set_memberEquality,  addEquality,  independent_functionElimination,  productElimination,  equalityTransitivity,  equalitySymmetry,  independent_isectElimination,  independent_pairFormation,  unionElimination,  voidElimination,  isect_memberEquality,  voidEquality,  intEquality,  minusEquality,  cumulativity,  universeEquality,  dependent_set_memberFormation,  dependent_pairFormation,  addLevel,  hyp_replacement,  levelHypothesis,  equalityElimination,  lessCases,  axiomSqEquality,  promote_hyp,  instantiate,  cutEval,  multiplyEquality

Latex:
\mforall{}[X:n:\mBbbN{}  {}\mrightarrow{}  (\mBbbN{}n  {}\mrightarrow{}  \mBbbB{})  {}\mrightarrow{}  \mBbbP{}]
    (\mforall{}n:\mBbbN{}.  \mforall{}s:\mBbbN{}n  {}\mrightarrow{}  \mBbbB{}.    Dec(X[n;s]))  {}\mRightarrow{}  (\mexists{}k:\mBbbN{}  [(\mforall{}f:\mBbbN{}  {}\mrightarrow{}  \mBbbB{}.  \mexists{}n:\mBbbN{}k.  X[n;f])]) 
    supposing  \mforall{}f:\mBbbN{}  {}\mrightarrow{}  \mBbbB{}.  (\mdownarrow{}\mexists{}n:\mBbbN{}.  X[n;f])



Date html generated: 2019_06_20-AM-11_32_31
Last ObjectModification: 2018_08_20-PM-09_32_25

Theory : bool_1


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