Nuprl Lemma : TC-equiv-is-equiv

[T:Type]. ∀[R:T ⟶ T ⟶ ℙ].
  (rel-diamond-property(T;x,y.R y)
   (∃m:T ⟶ ℕ. ∀x,y:T.  ((R y)  y < x))
   EquivRel(T;a,b.confluent-equiv(T;x,y.R^* y) b))


Proof




Definitions occuring in Statement :  confluent-equiv: confluent-equiv(T;x,y.R[x; y]) rel-diamond-property: rel-diamond-property(T;x,y.R[x; y]) transitive-reflexive-closure: R^* equiv_rel: EquivRel(T;x,y.E[x; y]) nat: less_than: a < b uall: [x:A]. B[x] prop: all: x:A. B[x] exists: x:A. B[x] implies:  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_lambda: λ2y.t[x; y] so_apply: x[s1;s2] exists: x:A. B[x] all: x:A. B[x] subtype_rel: A ⊆B prop: nat: refl: Refl(T;x,y.E[x; y]) transitive-reflexive-closure: R^* or: P ∨ Q trans: Trans(T;x,y.E[x; y]) infix_ap: y
Lemmas referenced :  confluent-equiv-is-equiv transitive-reflexive-closure_wf istype-nat subtype_rel_self istype-less_than rel-diamond-property_wf istype-universe transitive-closure_wf transitive-reflexive-closure_transitivity diamond-implies-TC-confluent eta_conv rel-confluent_wf
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation_alt lambdaFormation_alt cut introduction extract_by_obid sqequalHypSubstitution isectElimination thin hypothesisEquality sqequalRule lambdaEquality_alt applyEquality hypothesis inhabitedIsType universeIsType independent_functionElimination productIsType functionIsType because_Cache instantiate universeEquality setElimination rename inlFormation_alt dependent_functionElimination functionExtensionality_alt cumulativity equalitySymmetry hyp_replacement applyLambdaEquality

Latex:
\mforall{}[T:Type].  \mforall{}[R:T  {}\mrightarrow{}  T  {}\mrightarrow{}  \mBbbP{}].
    (rel-diamond-property(T;x,y.R  x  y)
    {}\mRightarrow{}  (\mexists{}m:T  {}\mrightarrow{}  \mBbbN{}.  \mforall{}x,y:T.    ((R  x  y)  {}\mRightarrow{}  m  y  <  m  x))
    {}\mRightarrow{}  EquivRel(T;a,b.confluent-equiv(T;x,y.R\^{}*  x  y)  a  b))



Date html generated: 2019_10_15-AM-10_24_51
Last ObjectModification: 2019_08_16-PM-03_32_51

Theory : relations2


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