Nuprl Lemma : filter-filter2
∀[P1,P2,L:Top].  (filter(P2;filter(P1;L)) ~ filter(λt.((P1 t) ∧b (P2 t));L))
Proof
Definitions occuring in Statement : 
filter: filter(P;l)
, 
band: p ∧b q
, 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
apply: f a
, 
lambda: λx.A[x]
, 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
top: Top
Lemmas referenced : 
filter-filter, 
top_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
cut, 
lemma_by_obid, 
sqequalHypSubstitution, 
sqequalTransitivity, 
computationStep, 
isectElimination, 
thin, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
hypothesis, 
isect_memberFormation, 
introduction, 
sqequalAxiom, 
hypothesisEquality, 
because_Cache
Latex:
\mforall{}[P1,P2,L:Top].    (filter(P2;filter(P1;L))  \msim{}  filter(\mlambda{}t.((P1  t)  \mwedge{}\msubb{}  (P2  t));L))
Date html generated:
2016_05_14-PM-02_57_32
Last ObjectModification:
2015_12_26-PM-02_29_47
Theory : list_1
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