Nuprl Lemma : can-apply-p-lift
∀[A,B:Type]. ∀[P:A ⟶ ℙ].  ∀d:x:A ⟶ Dec(P[x]). ∀f:{x:A| P[x]}  ⟶ B. ∀x:A.  (↑can-apply(p-lift(d;f);x) ⇐⇒ P[x])
Proof
Definitions occuring in Statement : 
p-lift: p-lift(d;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, 
set: {x:A| B[x]} , 
function: x:A ⟶ B[x], 
universe: Type
Definitions unfolded in proof : 
p-lift: p-lift(d;f), 
can-apply: can-apply(f;x), 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
member: t ∈ T, 
so_apply: x[s], 
subtype_rel: A ⊆r B, 
prop: ℙ, 
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 : 
decidable_wf, 
true_wf, 
false_wf, 
equal_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
lambdaFormation, 
hypothesisEquality, 
functionEquality, 
setEquality, 
cut, 
applyEquality, 
hypothesis, 
thin, 
lambdaEquality, 
sqequalHypSubstitution, 
universeEquality, 
lemma_by_obid, 
isectElimination, 
cumulativity, 
unionElimination, 
independent_pairFormation, 
natural_numberEquality, 
voidElimination, 
independent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
dependent_functionElimination
Latex:
\mforall{}[A,B:Type].  \mforall{}[P:A  {}\mrightarrow{}  \mBbbP{}].
    \mforall{}d:x:A  {}\mrightarrow{}  Dec(P[x]).  \mforall{}f:\{x:A|  P[x]\}    {}\mrightarrow{}  B.  \mforall{}x:A.    (\muparrow{}can-apply(p-lift(d;f);x)  \mLeftarrow{}{}\mRightarrow{}  P[x])
Date html generated:
2016_05_15-PM-03_29_20
Last ObjectModification:
2015_12_27-PM-01_09_31
Theory : general
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