Nuprl Lemma : apply-alist-count-repeats
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[x:T]. ∀[L:T List].
  (apply-alist(eq;count-repeats(L,eq);x) = if x ∈b L then inl ||filter(λy.(eq y x);L)|| else inr ⋅  fi  ∈ (ℕ+?))
Proof
Definitions occuring in Statement : 
count-repeats: count-repeats(L,eq), 
apply-alist: apply-alist(eq;L;x), 
length: ||as||, 
deq-member: x ∈b L, 
filter: filter(P;l), 
list: T List, 
deq: EqDecider(T), 
nat_plus: ℕ+, 
ifthenelse: if b then t else f fi , 
it: ⋅, 
uall: ∀[x:A]. B[x], 
unit: Unit, 
apply: f a, 
lambda: λx.A[x], 
inr: inr x , 
inl: inl x, 
union: left + right, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
implies: P ⇒ Q, 
guard: {T}, 
all: ∀x:A. B[x], 
exposed-bfalse: exposed-bfalse, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
uimplies: b supposing a, 
iff: P ⇐⇒ Q, 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
exists: ∃x:A. B[x], 
or: P ∨ Q, 
sq_type: SQType(T), 
bnot: ¬bb, 
assert: ↑b, 
false: False, 
not: ¬A, 
rev_implies: P ⇐ Q, 
prop: ℙ, 
nat_plus: ℕ+, 
deq: EqDecider(T), 
eqof: eqof(d), 
rev_uimplies: rev_uimplies(P;Q), 
so_apply: x[s1;s2;s3], 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
so_apply: x[s1;s2], 
so_lambda: λ2x y.t[x; y], 
top: Top, 
apply-alist: apply-alist(eq;L;x), 
count-repeats: count-repeats(L,eq), 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
le: A ≤ B, 
subtract: n - m, 
decidable: Dec(P), 
true: True, 
less_than': less_than'(a;b), 
less_than: a < b, 
squash: ↓T, 
subtype_rel: A ⊆r B
Lemmas referenced : 
last_induction, 
list_wf, 
deq_wf, 
equal_wf, 
nat_plus_wf, 
unit_wf2, 
apply-alist_wf, 
count-repeats_wf, 
deq-member_wf, 
eqtt_to_assert, 
assert-deq-member, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
assert-bnot, 
l_member_wf, 
it_wf, 
length_wf, 
filter_wf5, 
member-exists2, 
member_filter, 
safe-assert-deq, 
less_than_wf, 
list_ind_nil_lemma, 
filter_nil_lemma, 
deq_member_nil_lemma, 
list_accum_nil_lemma, 
equal-wf-T-base, 
cons_member, 
length_of_nil_lemma, 
length_of_cons_lemma, 
member_append, 
append_back_nil, 
length-singleton, 
length-append, 
int_formula_prop_wf, 
int_term_value_var_lemma, 
int_term_value_add_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_and_lemma, 
itermVar_wf, 
itermAdd_wf, 
itermConstant_wf, 
intformless_wf, 
intformnot_wf, 
intformand_wf, 
satisfiable-full-omega-tt, 
filter_cons_lemma, 
filter_append_sq, 
iff_weakening_equal, 
le-add-cancel, 
add-zero, 
add-associates, 
add_functionality_wrt_le, 
add-commutes, 
minus-one-mul-top, 
zero-add, 
minus-one-mul, 
minus-add, 
condition-implies-le, 
less-iff-le, 
not-lt-2, 
false_wf, 
decidable__lt, 
apply-updated-alist, 
true_wf, 
squash_wf, 
list_accum_cons_lemma, 
top_wf, 
subtype_rel_list, 
list_accum_append, 
nil_wf, 
cons_wf, 
append_wf, 
and_wf, 
assert_wf, 
not_wf, 
l_all_iff, 
filter_is_nil, 
or_wf, 
member_singleton
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
thin, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
sqequalRule, 
independent_functionElimination, 
hypothesis, 
dependent_functionElimination, 
Error :universeIsType, 
Error :isect_memberEquality_alt, 
axiomEquality, 
because_Cache, 
universeEquality, 
Error :lambdaEquality_alt, 
unionEquality, 
Error :inhabitedIsType, 
Error :lambdaFormation_alt, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
independent_isectElimination, 
Error :inlEquality_alt, 
Error :dependent_pairFormation_alt, 
Error :equalityIsType1, 
promote_hyp, 
instantiate, 
cumulativity, 
voidElimination, 
Error :inrEquality_alt, 
Error :dependent_set_memberEquality_alt, 
setElimination, 
rename, 
applyEquality, 
Error :setIsType, 
independent_pairFormation, 
natural_numberEquality, 
inrEquality, 
voidEquality, 
isect_memberEquality, 
inrFormation, 
inlFormation, 
applyLambdaEquality, 
hyp_replacement, 
computeAll, 
int_eqEquality, 
inlEquality, 
minusEquality, 
intEquality, 
addEquality, 
baseClosed, 
imageMemberEquality, 
dependent_set_memberEquality, 
levelHypothesis, 
equalityUniverse, 
imageElimination, 
dependent_pairFormation, 
setEquality, 
lambdaEquality, 
lambdaFormation, 
addLevel, 
orFunctionality
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[x:T].  \mforall{}[L:T  List].
    (apply-alist(eq;count-repeats(L,eq);x)
    =  if  x  \mmember{}\msubb{}  L  then  inl  ||filter(\mlambda{}y.(eq  y  x);L)||  else  inr  \mcdot{}    fi  )
 Date html generated: 
2019_06_20-PM-01_54_46
 Last ObjectModification: 
2018_10_05-AM-10_55_37
Theory : decidable!equality
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