Nuprl Lemma : mapfilter-reduce
∀[f:Top]. ∀[T:Type]. ∀[L:T List]. ∀[P:{x:T| (x ∈ L)}  ⟶ 𝔹].
  (mapfilter(f;P;L) ~ reduce(λx,y. if P x then [f x / y] else y fi [];L))
Proof
Definitions occuring in Statement : 
mapfilter: mapfilter(f;P;L)
, 
l_member: (x ∈ l)
, 
reduce: reduce(f;k;as)
, 
cons: [a / b]
, 
nil: []
, 
list: T List
, 
ifthenelse: if b then t else f fi 
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
set: {x:A| B[x]} 
, 
apply: f a
, 
lambda: λx.A[x]
, 
function: x:A ⟶ B[x]
, 
universe: Type
, 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
nat: ℕ
, 
implies: P 
⇒ Q
, 
false: False
, 
ge: i ≥ j 
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
not: ¬A
, 
top: Top
, 
and: P ∧ Q
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
or: P ∨ Q
, 
mapfilter: mapfilter(f;P;L)
, 
cons: [a / b]
, 
colength: colength(L)
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
decidable: Dec(P)
, 
nil: []
, 
it: ⋅
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
sq_type: SQType(T)
, 
less_than: a < b
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
bool: 𝔹
, 
unit: Unit
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
bnot: ¬bb
, 
assert: ↑b
Lemmas referenced : 
nat_properties, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
ge_wf, 
less_than_wf, 
l_member_wf, 
bool_wf, 
equal-wf-T-base, 
nat_wf, 
colength_wf_list, 
less_than_transitivity1, 
less_than_irreflexivity, 
list-cases, 
reduce_nil_lemma, 
filter_nil_lemma, 
map_nil_lemma, 
nil_wf, 
product_subtype_list, 
spread_cons_lemma, 
intformeq_wf, 
itermAdd_wf, 
int_formula_prop_eq_lemma, 
int_term_value_add_lemma, 
decidable__le, 
intformnot_wf, 
int_formula_prop_not_lemma, 
le_wf, 
equal_wf, 
subtract_wf, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
subtype_base_sq, 
set_subtype_base, 
int_subtype_base, 
decidable__equal_int, 
reduce_cons_lemma, 
filter_cons_lemma, 
subtype_rel_dep_function, 
cons_wf, 
subtype_rel_sets, 
cons_member, 
subtype_rel_self, 
set_wf, 
eqtt_to_assert, 
map_cons_lemma, 
eqff_to_assert, 
bool_cases_sqequal, 
bool_subtype_base, 
assert-bnot, 
list_wf, 
top_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
thin, 
lambdaFormation, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
natural_numberEquality, 
independent_isectElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
sqequalRule, 
independent_pairFormation, 
computeAll, 
independent_functionElimination, 
sqequalAxiom, 
functionEquality, 
setEquality, 
cumulativity, 
applyEquality, 
because_Cache, 
unionElimination, 
promote_hyp, 
hypothesis_subsumption, 
productElimination, 
equalityTransitivity, 
equalitySymmetry, 
applyLambdaEquality, 
dependent_set_memberEquality, 
addEquality, 
baseClosed, 
instantiate, 
imageElimination, 
inrFormation, 
functionExtensionality, 
inlFormation, 
equalityElimination, 
universeEquality
Latex:
\mforall{}[f:Top].  \mforall{}[T:Type].  \mforall{}[L:T  List].  \mforall{}[P:\{x:T|  (x  \mmember{}  L)\}    {}\mrightarrow{}  \mBbbB{}].
    (mapfilter(f;P;L)  \msim{}  reduce(\mlambda{}x,y.  if  P  x  then  [f  x  /  y]  else  y  fi  ;[];L))
Date html generated:
2017_04_17-AM-07_25_33
Last ObjectModification:
2017_02_27-PM-04_04_22
Theory : list_1
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