Nuprl Lemma : filter-singleton
∀[x,P:Top]. (filter(P;[x]) ~ if P x then [x] else [] fi )
Proof
Definitions occuring in Statement :
filter: filter(P;l),
cons: [a / b],
nil: [],
ifthenelse: if b then t else f fi ,
uall: ∀[x:A]. B[x],
top: Top,
apply: f a,
sqequal: s ~ t
Definitions unfolded in proof :
filter: filter(P;l),
all: ∀x:A. B[x],
member: t ∈ T,
top: Top,
uall: ∀[x:A]. B[x]
Lemmas referenced :
reduce_cons_lemma,
reduce_nil_lemma,
top_wf
Rules used in proof :
sqequalSubstitution,
sqequalRule,
sqequalReflexivity,
sqequalTransitivity,
computationStep,
cut,
lemma_by_obid,
sqequalHypSubstitution,
dependent_functionElimination,
thin,
isect_memberEquality,
voidElimination,
voidEquality,
hypothesis,
isect_memberFormation,
introduction,
sqequalAxiom,
isectElimination,
hypothesisEquality,
because_Cache
Latex:
\mforall{}[x,P:Top]. (filter(P;[x]) \msim{} if P x then [x] else [] fi )
Date html generated:
2016_05_14-PM-02_57_45
Last ObjectModification:
2015_12_26-PM-02_30_06
Theory : list_1
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