Nuprl Lemma : AF-induction

[T:Type]. ∀[R:T ⟶ T ⟶ ℙ].
  (∀[Q:T ⟶ ℙ]. TI(T;x,y.¬R[x;y];t.Q[t])) supposing 
     (AFx,y:T.R[x;y] and 
     (∀x,y,z:T.  ((¬R[x;y])  R[y;z])  R[x;z]))))


Proof




Definitions occuring in Statement :  almost-full: AFx,y:T.R[x; y] TI: TI(T;x,y.R[x; y];t.Q[t]) uimplies: supposing a uall: [x:A]. B[x] prop: so_apply: x[s1;s2] so_apply: x[s] all: x:A. B[x] not: ¬A implies:  Q function: x:A ⟶ B[x] universe: Type
Definitions unfolded in proof :  uall: [x:A]. B[x] uimplies: supposing a member: t ∈ T all: x:A. B[x] implies:  Q not: ¬A false: False so_apply: x[s1;s2] subtype_rel: A ⊆B prop: almost-full: AFx,y:T.R[x; y] squash: T TI: TI(T;x,y.R[x; y];t.Q[t]) so_lambda: λ2y.t[x; y] consistent-seq: R-consistent-seq(n) so_lambda: λ2x.t[x] so_apply: x[s] exists: x:A. B[x] seq-add: s.x@n AF-spread-law: AF-spread-law(x,y.R[x; y]) isl: isl(x) outl: outl(x) assert: b ifthenelse: if then else fi  btrue: tt int_seg: {i..j-} nat: bool: 𝔹 unit: Unit it: uiff: uiff(P;Q) and: P ∧ Q cand: c∧ B true: True bfalse: ff or: P ∨ Q sq_type: SQType(T) guard: {T} bnot: ¬bb iff: ⇐⇒ Q rev_implies:  Q lelt: i ≤ j < k le: A ≤ B decidable: Dec(P) less_than': less_than'(a;b) subtract: m sq_stable: SqStable(P) top: Top less_than: a < b
Lemmas referenced :  not_wf nat_wf AF-spread-law_wf AFbar_wf basic_strong_bar_induction unit_wf2 all_wf consistent-seq_wf decidable__AFbar at_AFbar AF-path-barred almost-full_wf eq_int_wf bool_wf eqtt_to_assert assert_of_eq_int eqff_to_assert equal_wf bool_cases_sqequal subtype_base_sq bool_subtype_base iff_transitivity assert_wf bnot_wf iff_weakening_uiff assert_of_bnot outl_wf decidable__lt false_wf not-lt-2 not-equal-2 add_functionality_wrt_le add-swap add-commutes le-add-cancel less-iff-le condition-implies-le add-associates minus-add minus-one-mul minus-one-mul-top zero-add le-add-cancel2 int_seg_wf true_wf decidable__le not-le-2 sq_stable__le add-zero le_wf seq-add_wf set_wf and_wf less_than_wf 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 voidElimination applyEquality functionExtensionality cumulativity hypothesis universeEquality extract_by_obid isectElimination rename imageElimination imageMemberEquality baseClosed functionEquality lambdaFormation because_Cache unionEquality equalityTransitivity equalitySymmetry setEquality setElimination inlEquality independent_functionElimination dependent_set_memberEquality unionElimination equalityElimination productElimination independent_isectElimination int_eqReduceTrueSq natural_numberEquality independent_pairFormation dependent_pairFormation promote_hyp instantiate intEquality impliesFunctionality int_eqReduceFalseSq addEquality minusEquality isect_memberEquality voidEquality productEquality

Latex:
\mforall{}[T:Type].  \mforall{}[R:T  {}\mrightarrow{}  T  {}\mrightarrow{}  \mBbbP{}].
    (\mforall{}[Q:T  {}\mrightarrow{}  \mBbbP{}].  TI(T;x,y.\mneg{}R[x;y];t.Q[t]))  supposing 
          (AFx,y:T.R[x;y]  and 
          (\mforall{}x,y,z:T.    ((\mneg{}R[x;y])  {}\mRightarrow{}  (\mneg{}R[y;z])  {}\mRightarrow{}  (\mneg{}R[x;z]))))



Date html generated: 2017_04_14-AM-07_27_57
Last ObjectModification: 2017_02_27-PM-02_57_29

Theory : bar-induction


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