Nuprl Lemma : filter_wf
∀[T:Type]. ∀[l:T List]. ∀[P:T ⟶ 𝔹].  (filter(P;l) ∈ T List)
Proof
Definitions occuring in Statement : 
filter: filter(P;l)
, 
list: T List
, 
bool: 𝔹
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
filter: filter(P;l)
Lemmas referenced : 
reduce_wf, 
list_wf, 
ifthenelse_wf, 
cons_wf, 
nil_wf, 
bool_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
sqequalRule, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
lambdaEquality, 
applyEquality, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
Error :functionIsType, 
Error :universeIsType, 
isect_memberEquality, 
functionEquality, 
because_Cache, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[l:T  List].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].    (filter(P;l)  \mmember{}  T  List)
Date html generated:
2019_06_20-PM-00_39_13
Last ObjectModification:
2018_09_26-PM-02_05_47
Theory : list_0
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