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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