Nuprl Lemma : decidable-exists-finite
∀[T:Type]. (finite(T) 
⇒ (∀[P:T ⟶ ℙ]. ((∀t:T. Dec(P[t])) 
⇒ Dec(∃t:T. P[t]))))
Proof
Definitions occuring in Statement : 
finite: finite(T)
, 
decidable: Dec(P)
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
implies: P 
⇒ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
prop: ℙ
, 
finite: finite(T)
, 
exists: ∃x:A. B[x]
, 
finite-type: finite-type(T)
, 
nat: ℕ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
guard: {T}
, 
equipollent: A ~ B
, 
biject: Bij(A;B;f)
, 
and: P ∧ Q
Lemmas referenced : 
decidable-exists-finite-type, 
finite_wf, 
exists_wf, 
int_seg_wf, 
surject_wf, 
equipollent_inversion
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
lambdaFormation, 
independent_functionElimination, 
cumulativity, 
universeEquality, 
productElimination, 
dependent_pairFormation, 
functionEquality, 
natural_numberEquality, 
setElimination, 
rename, 
sqequalRule, 
lambdaEquality, 
because_Cache, 
functionExtensionality, 
applyEquality
Latex:
\mforall{}[T:Type].  (finite(T)  {}\mRightarrow{}  (\mforall{}[P:T  {}\mrightarrow{}  \mBbbP{}].  ((\mforall{}t:T.  Dec(P[t]))  {}\mRightarrow{}  Dec(\mexists{}t:T.  P[t]))))
Date html generated:
2016_10_21-AM-11_00_13
Last ObjectModification:
2016_08_08-AM-11_27_08
Theory : equipollence!!cardinality!
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