Nuprl Lemma : apply_alist_wf
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[x:T]. ∀[V:Type]. ∀[L:(T × V) List].
  apply_alist(eq;L;x) ∈ {v:V| (<x, v> ∈ L)}  supposing (x ∈ map(λa.(fst(a));L))
Proof
Definitions occuring in Statement : 
apply_alist: apply_alist(eq;L;x)
, 
l_member: (x ∈ l)
, 
map: map(f;as)
, 
list: T List
, 
deq: EqDecider(T)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
pi1: fst(t)
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
lambda: λx.A[x]
, 
pair: <a, b>
, 
product: x:A × B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
nat: ℕ
, 
implies: P 
⇒ Q
, 
false: False
, 
and: P ∧ Q
, 
ge: i ≥ j 
, 
le: A ≤ B
, 
cand: A c∧ B
, 
less_than: a < b
, 
squash: ↓T
, 
guard: {T}
, 
uimplies: b supposing a
, 
prop: ℙ
, 
or: P ∨ Q
, 
top: Top
, 
not: ¬A
, 
cons: [a / b]
, 
less_than': less_than'(a;b)
, 
colength: colength(L)
, 
nil: []
, 
it: ⋅
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
sq_type: SQType(T)
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
sq_stable: SqStable(P)
, 
subtract: n - m
, 
subtype_rel: A ⊆r B
, 
iff: P 
⇐⇒ Q
, 
pi1: fst(t)
, 
apply_alist: apply_alist(eq;L;x)
, 
deq: EqDecider(T)
, 
bool: 𝔹
, 
uiff: uiff(P;Q)
, 
rev_implies: P 
⇐ Q
, 
true: True
, 
assert: ↑b
, 
ifthenelse: if b then t else f fi 
Lemmas referenced : 
nat_properties, 
less_than_transitivity1, 
less_than_irreflexivity, 
ge_wf, 
istype-less_than, 
list-cases, 
map_nil_lemma, 
istype-void, 
null_nil_lemma, 
btrue_wf, 
member-implies-null-eq-bfalse, 
nil_wf, 
btrue_neq_bfalse, 
l_member_wf, 
product_subtype_list, 
colength-cons-not-zero, 
colength_wf_list, 
istype-false, 
istype-le, 
subtract-1-ge-0, 
subtype_base_sq, 
nat_wf, 
set_subtype_base, 
le_wf, 
int_subtype_base, 
spread_cons_lemma, 
sq_stable__le, 
add-associates, 
add-commutes, 
add-swap, 
zero-add, 
map_cons_lemma, 
cons_member, 
map_wf, 
pi1_wf, 
deq_property, 
equal_wf, 
squash_wf, 
true_wf, 
subtype_rel_self, 
iff_weakening_equal, 
cons_wf, 
istype-assert, 
le_weakening2, 
istype-nat, 
list_wf, 
deq_wf, 
istype-universe, 
subtype_rel_sets_simple
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
thin, 
Error :lambdaFormation_alt, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
sqequalRule, 
intWeakElimination, 
independent_pairFormation, 
productElimination, 
imageElimination, 
natural_numberEquality, 
independent_isectElimination, 
independent_functionElimination, 
voidElimination, 
Error :universeIsType, 
Error :lambdaEquality_alt, 
dependent_functionElimination, 
Error :isect_memberEquality_alt, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
Error :isectIsTypeImplies, 
Error :inhabitedIsType, 
Error :functionIsTypeImplies, 
productEquality, 
unionElimination, 
promote_hyp, 
hypothesis_subsumption, 
Error :equalityIstype, 
because_Cache, 
Error :dependent_set_memberEquality_alt, 
instantiate, 
cumulativity, 
intEquality, 
imageMemberEquality, 
baseClosed, 
applyLambdaEquality, 
baseApply, 
closedConclusion, 
applyEquality, 
sqequalBase, 
independent_pairEquality, 
Error :inlFormation_alt, 
universeEquality, 
Error :productIsType, 
Error :isectIsType, 
Error :inrFormation_alt
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[x:T].  \mforall{}[V:Type].  \mforall{}[L:(T  \mtimes{}  V)  List].
    apply\_alist(eq;L;x)  \mmember{}  \{v:V|  (<x,  v>  \mmember{}  L)\}    supposing  (x  \mmember{}  map(\mlambda{}a.(fst(a));L))
Date html generated:
2019_06_20-PM-00_42_44
Last ObjectModification:
2019_02_28-PM-00_01_09
Theory : list_0
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