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 y) ⇐⇒ E[x;y]))


Proof




Definitions occuring in Statement :  assert: b bool: 𝔹 decidable: Dec(P) uall: [x:A]. B[x] prop: infix_ap: y so_apply: x[s1;s2] all: x:A. B[x] exists: x:A. B[x] iff: ⇐⇒ Q function: x:A ⟶ B[x] universe: Type
Definitions unfolded in proof :  all: x:A. B[x] rev_implies:  Q so_apply: x[s] so_lambda: λ2x.t[x] prop: member: t ∈ T implies:  Q and: P ∧ Q iff: ⇐⇒ Q uall: [x:A]. B[x] infix_ap: y so_apply: x[s1;s2] or: P ∨ Q subtype_rel: A ⊆B exists: x:A. B[x] decidable: Dec(P) true: True btrue: tt ifthenelse: if then else 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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