Nuprl Lemma : filter-commutes

∀[T:Type]. ∀[P1,P2:T ⟶ 𝔹]. ∀[L:T List].  (filter(P1;filter(P2;L)) ~ filter(P2;filter(P1;L)))


Proof




Definitions occuring in Statement :  filter: filter(P;l),  list: T List,  bool: 𝔹,  uall: ∀[x:A]. B[x],  function: x:A ⟶ B[x],  universe: Type,  sqequal: s ~ t
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T
Lemmas referenced :  swap-filter-filter,  list_wf,  bool_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  lemma_by_obid,  sqequalHypSubstitution,  isectElimination,  thin,  hypothesisEquality,  hypothesis,  sqequalAxiom,  sqequalRule,  isect_memberEquality,  because_Cache,  functionEquality,  universeEquality

Latex:
\mforall{}[T:Type].  \mforall{}[P1,P2:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[L:T  List].    (filter(P1;filter(P2;L))  \msim{}  filter(P2;filter(P1;L)))



Date html generated: 2016_05_15-PM-03_40_17
Last ObjectModification: 2015_12_27-PM-01_16_42

Theory : general


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