Nuprl Lemma : wellfounded-minimal

[T:Type]. ∀[R:T ⟶ T ⟶ ℙ]. ∀[P:T ⟶ ℙ].
  ((∀x,y:T.  Dec(R y))
   (∀x:T. Dec(P x))
   (∀y:T. ∃L:T List. ∀x:T. ((R y)  (x ∈ L)))
   WellFnd{i}(T;x,y.R y)
   (∀z:T. ((P z)  (∃y:T. ((P y) ∧ ((R^*) z) ∧ (∀x:T. ((R+ y)  (P x)))))))))


Proof




Definitions occuring in Statement :  rel_plus: R+ l_member: (x ∈ l) list: List rel_star: R^* wellfounded: WellFnd{i}(A;x,y.R[x; y]) decidable: Dec(P) uall: [x:A]. B[x] prop: all: x:A. B[x] exists: x:A. B[x] not: ¬A implies:  Q and: P ∧ Q apply: a function: x:A ⟶ B[x] universe: Type
Definitions unfolded in proof :  uall: [x:A]. B[x] implies:  Q member: t ∈ T so_apply: x[s] all: x:A. B[x] wellfounded: WellFnd{i}(A;x,y.R[x; y]) so_lambda: λ2x.t[x] prop: and: P ∧ Q subtype_rel: A ⊆B exists: x:A. B[x] guard: {T} so_lambda: λ2y.t[x; y] so_apply: x[s1;s2] decidable: Dec(P) or: P ∨ Q infix_ap: y cand: c∧ B uimplies: supposing a not: ¬A false: False iff: ⇐⇒ Q
Lemmas referenced :  decidable__wellfound-bounded-exists exists_wf rel_star_wf all_wf rel_plus_wf not_wf wellfounded_wf list_wf l_member_wf decidable_wf rel_plus_implies rel_star_transitivity rel_star_weakening rel-plus-rel-star rel_rel_star rel-star-iff-rel-plus-or
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation lambdaFormation cut introduction extract_by_obid sqequalHypSubstitution isectElimination thin hypothesisEquality independent_functionElimination hypothesis sqequalRule lambdaEquality functionEquality cumulativity productEquality applyEquality because_Cache functionExtensionality rename universeEquality dependent_functionElimination unionElimination productElimination dependent_pairFormation independent_pairFormation promote_hyp independent_isectElimination voidElimination equalitySymmetry hyp_replacement Error :applyLambdaEquality

Latex:
\mforall{}[T:Type].  \mforall{}[R:T  {}\mrightarrow{}  T  {}\mrightarrow{}  \mBbbP{}].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbP{}].
    ((\mforall{}x,y:T.    Dec(R  x  y))
    {}\mRightarrow{}  (\mforall{}x:T.  Dec(P  x))
    {}\mRightarrow{}  (\mforall{}y:T.  \mexists{}L:T  List.  \mforall{}x:T.  ((R  x  y)  {}\mRightarrow{}  (x  \mmember{}  L)))
    {}\mRightarrow{}  WellFnd\{i\}(T;x,y.R  x  y)
    {}\mRightarrow{}  (\mforall{}z:T.  ((P  z)  {}\mRightarrow{}  (\mexists{}y:T.  ((P  y)  \mwedge{}  (rel\_star(T;  R)  y  z)  \mwedge{}  (\mforall{}x:T.  ((R\msupplus{}  x  y)  {}\mRightarrow{}  (\mneg{}(P  x)))))))))



Date html generated: 2016_10_25-AM-11_00_33
Last ObjectModification: 2016_07_12-AM-07_07_41

Theory : general


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