Nuprl Lemma : can-apply-p-filter
∀[T:Type]. ∀[P:T ⟶ ℙ].  ∀f:∀x:T. Dec(P[x]). ∀x:T.  (↑can-apply(p-filter(f);x) 
⇐⇒ P[x])
Proof
Definitions occuring in Statement : 
p-filter: p-filter(f)
, 
can-apply: can-apply(f;x)
, 
assert: ↑b
, 
decidable: Dec(P)
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
p-filter: p-filter(f)
, 
can-apply: can-apply(f;x)
, 
member: t ∈ T
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
implies: P 
⇒ Q
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
isl: isl(x)
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
rev_implies: P 
⇐ Q
, 
true: True
, 
bfalse: ff
, 
false: False
, 
not: ¬A
Lemmas referenced : 
all_wf, 
decidable_wf, 
true_wf, 
false_wf, 
equal_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
sqequalRule, 
hypothesisEquality, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
lambdaEquality, 
applyEquality, 
hypothesis, 
functionEquality, 
cumulativity, 
universeEquality, 
unionElimination, 
independent_pairFormation, 
natural_numberEquality, 
voidElimination, 
independent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
dependent_functionElimination
Latex:
\mforall{}[T:Type].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbP{}].    \mforall{}f:\mforall{}x:T.  Dec(P[x]).  \mforall{}x:T.    (\muparrow{}can-apply(p-filter(f);x)  \mLeftarrow{}{}\mRightarrow{}  P[x])
Date html generated:
2016_05_15-PM-03_30_55
Last ObjectModification:
2015_12_27-PM-01_10_54
Theory : general
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