Nuprl Lemma : can-apply-p-first
∀[A,B:Type].  ∀L:(A ⟶ (B + Top)) List. ∀x:A.  (↑can-apply(p-first(L);x) 
⇐⇒ (∃f∈L. ↑can-apply(f;x)))
Proof
Definitions occuring in Statement : 
p-first: p-first(L)
, 
can-apply: can-apply(f;x)
, 
l_exists: (∃x∈L. P[x])
, 
list: T List
, 
assert: ↑b
, 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
all: ∀x:A. B[x]
, 
iff: P 
⇐⇒ Q
, 
function: x:A ⟶ B[x]
, 
union: left + right
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
member: t ∈ T
, 
so_lambda: λ2x.t[x]
, 
subtype_rel: A ⊆r B
, 
uimplies: b supposing a
, 
so_apply: x[s]
, 
top: Top
, 
prop: ℙ
, 
implies: P 
⇒ Q
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
iff: P 
⇐⇒ Q
, 
and: P ∧ Q
, 
false: False
, 
rev_implies: P 
⇐ Q
, 
append: as @ bs
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
so_apply: x[s1;s2;s3]
, 
or: P ∨ Q
, 
squash: ↓T
, 
true: True
, 
guard: {T}
, 
uiff: uiff(P;Q)
Lemmas referenced : 
p-first-singleton, 
p-first-append, 
true_wf, 
squash_wf, 
append_wf, 
l_exists_append, 
l_exists_cons, 
p-conditional-to-p-first, 
assert_functionality_wrt_uiff, 
or_wf, 
p-conditional_wf, 
nil_wf, 
cons_wf, 
p-conditional-domain, 
list_ind_nil_lemma, 
list_ind_cons_lemma, 
l_exists_wf_nil, 
l_exists_nil, 
false_wf, 
p_first_nil_lemma, 
list_wf, 
l_member_wf, 
l_exists_wf, 
subtype_rel_union, 
subtype_rel_dep_function, 
subtype_rel_list, 
p-first_wf, 
can-apply_wf, 
assert_wf, 
iff_wf, 
all_wf, 
top_wf, 
list_induction
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
thin, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
functionEquality, 
hypothesisEquality, 
unionEquality, 
hypothesis, 
sqequalRule, 
lambdaEquality, 
cumulativity, 
because_Cache, 
applyEquality, 
independent_isectElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
setElimination, 
rename, 
setEquality, 
independent_functionElimination, 
dependent_functionElimination, 
universeEquality, 
introduction, 
independent_pairFormation, 
productElimination, 
independent_pairEquality, 
addLevel, 
allFunctionality, 
impliesFunctionality, 
imageElimination, 
equalitySymmetry, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
orFunctionality, 
equalityTransitivity, 
unionElimination, 
inlFormation, 
inrFormation
Latex:
\mforall{}[A,B:Type].
    \mforall{}L:(A  {}\mrightarrow{}  (B  +  Top))  List.  \mforall{}x:A.    (\muparrow{}can-apply(p-first(L);x)  \mLeftarrow{}{}\mRightarrow{}  (\mexists{}f\mmember{}L.  \muparrow{}can-apply(f;x)))
Date html generated:
2016_05_15-PM-03_45_17
Last ObjectModification:
2016_01_16-AM-10_56_40
Theory : general
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