Nuprl Lemma : W-uwellfounded_witness

λF.fix(F) ∈ ∀[A:Type]. ∀[B:A ⟶ Type].  uWellFnd(W(A;a.B[a]);w1,w2.w1 <  w2)


Proof




Definitions occuring in Statement :  Wcmp: Wcmp(A;a.B[a];leq),  W: W(A;a.B[a]),  bfalse: ff,  uwellfounded: uWellFnd(A;x,y.R[x; y]),  uall: ∀[x:A]. B[x],  infix_ap: x f y,  so_apply: x[s],  member: t ∈ T,  fix: fix(F),  lambda: λx.A[x],  function: x:A ⟶ B[x],  universe: Type
Definitions unfolded in proof :  uwellfounded: uWellFnd(A;x,y.R[x; y]),  uall: ∀[x:A]. B[x],  member: t ∈ T,  all: ∀x:A. B[x],  so_lambda: λ2x.t[x],  so_apply: x[s],  prop: ℙ,  implies: P ⇒ Q,  subtype_rel: A ⊆r B,  infix_ap: x f y,  uimplies: b supposing a,  Wcmp: Wcmp(A;a.B[a];leq),  Wsup: Wsup(a;b),  ifthenelse: if b then t else f fi ,  bfalse: ff,  exists: ∃x:A. B[x],  and: P ∧ Q,  nat: ℕ,  pcw-pp-barred: Barred(pp),  int_seg: {i..j-},  lelt: i ≤ j < k,  decidable: Dec(P),  or: P ∨ Q,  iff: P ⇐⇒ Q,  not: ¬A,  rev_implies: P ⇐ Q,  false: False,  uiff: uiff(P;Q),  subtract: n - m,  top: Top,  le: A ≤ B,  less_than': less_than'(a;b),  true: True,  cw-step: cw-step(A;a.B[a]),  pcw-step: pcw-step(P;p.A[p];p,a.B[p; a];p,a,b.C[p; a; b]),  spreadn: spread3,  less_than: a < b,  squash: ↓T,  isr: isr(x),  assert: ↑b,  btrue: tt,  ext-eq: A ≡ B,  unit: Unit,  it: ⋅,  so_lambda: λ2x y.t[x; y],  so_apply: x[s1;s2],  so_lambda: so_lambda(x,y,z.t[x; y; z]),  so_apply: x[s1;s2;s3],  ext-family: F ≡ G,  pi1: fst(t),  nat_plus: ℕ+,  guard: {T},  W-rel: W-rel(A;a.B[a];w),  param-W-rel: param-W-rel(P;p.A[p];p,a.B[p; a];p,a,b.C[p; a; b];par;w),  pcw-steprel: StepRel(s1;s2),  pi2: snd(t),  isl: isl(x),  pcw-step-agree: StepAgree(s;p1;w),  cand: A c∧ B,  sq_type: SQType(T),  sq_stable: SqStable(P)
Lemmas referenced :  W_wf,  isect_wf,  infix_ap_wf,  Wcmp_wf,  bfalse_wf,  void_wf,  Wleq_weakening2,  Wsup_wf,  W-elimination-facts,  int_seg_wf,  subtract_wf,  decidable__le,  false_wf,  not-le-2,  less-iff-le,  condition-implies-le,  minus-one-mul,  zero-add,  minus-one-mul-top,  nat_wf,  minus-add,  minus-minus,  add-associates,  add-swap,  add-commutes,  add_functionality_wrt_le,  add-zero,  le-add-cancel,  decidable__lt,  not-lt-2,  add-mul-special,  zero-mul,  le-add-cancel-alt,  lelt_wf,  top_wf,  less_than_wf,  true_wf,  equal_wf,  add-subtract-cancel,  W-ext,  param-co-W-ext,  unit_wf2,  it_wf,  param-co-W_wf,  ext-eq_inversion,  subtype_rel_weakening,  assert_wf,  btrue_wf,  pcw-steprel_wf,  subtype_rel_dep_function,  subtype_base_sq,  set_subtype_base,  le_wf,  int_subtype_base,  decidable__int_equal,  not-equal-2,  minus-zero,  le-add-cancel2,  int_seg_subtype,  sq_stable__le,  Wcmp_transitivity,  set_wf
Rules used in proof :  sqequalSubstitution,  sqequalRule,  sqequalReflexivity,  sqequalTransitivity,  computationStep,  isect_memberEquality,  cut,  lambdaFormation,  rename,  thin,  sqequalHypSubstitution,  dependent_functionElimination,  hypothesisEquality,  equalityTransitivity,  hypothesis,  equalitySymmetry,  introduction,  extract_by_obid,  isectElimination,  cumulativity,  lambdaEquality,  applyEquality,  functionExtensionality,  because_Cache,  functionEquality,  isectEquality,  setEquality,  instantiate,  universeEquality,  setElimination,  voidElimination,  independent_functionElimination,  independent_isectElimination,  productElimination,  strong_bar_Induction,  natural_numberEquality,  dependent_set_memberEquality,  independent_pairFormation,  unionElimination,  addEquality,  voidEquality,  minusEquality,  intEquality,  lessCases,  isect_memberFormation,  sqequalAxiom,  imageMemberEquality,  baseClosed,  imageElimination,  axiomEquality,  int_eqReduceTrueSq,  promote_hyp,  hypothesis_subsumption,  equalityElimination,  dependent_pairEquality,  productEquality,  inlEquality,  unionEquality,  hyp_replacement,  applyLambdaEquality

Latex:
\mlambda{}F.fix(F)  \mmember{}  \mforall{}[A:Type].  \mforall{}[B:A  {}\mrightarrow{}  Type].    uWellFnd(W(A;a.B[a]);w1,w2.w1  <    w2)



Date html generated: 2017_04_14-AM-07_43_57
Last ObjectModification: 2017_02_27-PM-03_14_58

Theory : co-recursion


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