Nuprl Lemma : mapfilter_wf
∀[T:Type]. ∀[L:T List]. ∀[P:T ⟶ 𝔹]. ∀[T':Type]. ∀[f:{x:T| ↑(P x)}  ⟶ T'].  (mapfilter(f;P;L) ∈ T' List)
Proof
Definitions occuring in Statement : 
mapfilter: mapfilter(f;P;L)
, 
list: T List
, 
assert: ↑b
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
apply: f a
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
mapfilter: mapfilter(f;P;L)
, 
prop: ℙ
Lemmas referenced : 
filter_type, 
map_wf, 
assert_wf, 
bool_wf, 
list_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
setEquality, 
applyEquality, 
hypothesis, 
sqequalRule, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
Error :functionIsType, 
Error :setIsType, 
Error :universeIsType, 
isect_memberEquality, 
functionEquality, 
Error :inhabitedIsType, 
because_Cache, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[L:T  List].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[T':Type].  \mforall{}[f:\{x:T|  \muparrow{}(P  x)\}    {}\mrightarrow{}  T'].
    (mapfilter(f;P;L)  \mmember{}  T'  List)
Date html generated:
2019_06_20-PM-01_24_59
Last ObjectModification:
2018_09_26-PM-05_28_58
Theory : list_1
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