Nuprl Lemma : filter_wf5
∀[T:Type]. ∀[l:T List]. ∀[P:{x:T| (x ∈ l)}  ⟶ 𝔹].  (filter(P;l) ∈ T List)
Proof
Definitions occuring in Statement : 
l_member: (x ∈ l)
, 
filter: filter(P;l)
, 
list: T List
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
uimplies: b supposing a
Lemmas referenced : 
l_member_wf, 
bool_wf, 
list_wf, 
filter_wf, 
list-subtype, 
subtype_rel_list
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalHypSubstitution, 
hypothesis, 
sqequalRule, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
functionEquality, 
setEquality, 
hypothesisEquality, 
lemma_by_obid, 
isectElimination, 
thin, 
isect_memberEquality, 
because_Cache, 
universeEquality, 
cumulativity, 
applyEquality, 
independent_isectElimination, 
lambdaEquality, 
setElimination, 
rename
Latex:
\mforall{}[T:Type].  \mforall{}[l:T  List].  \mforall{}[P:\{x:T|  (x  \mmember{}  l)\}    {}\mrightarrow{}  \mBbbB{}].    (filter(P;l)  \mmember{}  T  List)
Date html generated:
2016_05_14-AM-06_39_43
Last ObjectModification:
2015_12_26-PM-00_31_49
Theory : list_0
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