Nuprl Lemma : dec_iff_ex_bvfun

∀[T:Type]. ∀[E:T ⟶ T ⟶ ℙ].  (∀x,y:T.  Dec(E[x;y]) ⇐⇒ ∃f:T ⟶ T ⟶ 𝔹. ∀x,y:T.  (↑(x f y) ⇐⇒ E[x;y]))


Proof




Definitions occuring in Statement :  assert: ↑b,  bool: 𝔹,  decidable: Dec(P),  uall: ∀[x:A]. B[x],  prop: ℙ,  infix_ap: x f y,  so_apply: x[s1;s2],  all: ∀x:A. B[x],  exists: ∃x:A. B[x],  iff: P ⇐⇒ Q,  function: x:A ⟶ B[x],  universe: Type
Definitions unfolded in proof :  all: ∀x:A. B[x],  rev_implies: P ⇐ Q,  so_apply: x[s],  so_lambda: λ2x.t[x],  prop: ℙ,  member: t ∈ T,  implies: P ⇒ Q,  and: P ∧ Q,  iff: P ⇐⇒ Q,  uall: ∀[x:A]. B[x],  infix_ap: x f y,  so_apply: x[s1;s2],  or: P ∨ Q,  subtype_rel: A ⊆r B,  exists: ∃x:A. B[x],  decidable: Dec(P),  true: True,  btrue: tt,  ifthenelse: if b then t else f fi ,  assert: ↑b,  not: ¬A,  false: False,  bfalse: ff
Lemmas referenced :  assert_wf,  iff_wf,  bool_wf,  exists_wf,  decidable_wf,  all_wf,  equal_wf,  bfalse_wf,  btrue_wf,  not_wf,  or_wf,  subtype_rel_self,  true_wf,  false_wf,  decidable_functionality,  decidable__assert
Rules used in proof :  universeEquality,  cumulativity,  functionEquality,  hypothesis,  applyEquality,  lambdaEquality,  hypothesisEquality,  thin,  isectElimination,  sqequalHypSubstitution,  extract_by_obid,  introduction,  cut,  lambdaFormation,  independent_pairFormation,  isect_memberFormation,  computationStep,  sqequalTransitivity,  sqequalReflexivity,  sqequalRule,  sqequalSubstitution,  independent_functionElimination,  dependent_functionElimination,  unionElimination,  instantiate,  unionEquality,  equalitySymmetry,  equalityTransitivity,  functionExtensionality,  dependent_pairFormation,  rename,  inlEquality,  applyLambdaEquality,  hyp_replacement,  natural_numberEquality,  inrEquality,  voidElimination,  productElimination

Latex:
\mforall{}[T:Type].  \mforall{}[E:T  {}\mrightarrow{}  T  {}\mrightarrow{}  \mBbbP{}].
    (\mforall{}x,y:T.    Dec(E[x;y])  \mLeftarrow{}{}\mRightarrow{}  \mexists{}f:T  {}\mrightarrow{}  T  {}\mrightarrow{}  \mBbbB{}.  \mforall{}x,y:T.    (\muparrow{}(x  f  y)  \mLeftarrow{}{}\mRightarrow{}  E[x;y]))



Date html generated: 2019_06_20-PM-00_32_14
Last ObjectModification: 2018_10_15-PM-05_02_36

Theory : quot_1


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