Nuprl Lemma : filter-union

[T:Type]. ∀eq:EqDecider(T). ∀as,bs:T List. ∀P:T ⟶ 𝔹.  (filter(P;as ⋃ bs) filter(P;as) ⋃ filter(P;bs) ∈ (T List))


Proof




Definitions occuring in Statement :  l-union: as ⋃ bs filter: filter(P;l) list: List deq: EqDecider(T) bool: 𝔹 uall: [x:A]. B[x] all: x:A. B[x] function: x:A ⟶ B[x] universe: Type equal: t ∈ T
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T all: x:A. B[x] l-union: as ⋃ bs so_lambda: λ2x.t[x] subtype_rel: A ⊆B so_apply: x[s] prop: uimplies: supposing a implies:  Q top: Top bool: 𝔹 unit: Unit it: btrue: tt uiff: uiff(P;Q) and: P ∧ Q ifthenelse: if then else fi  bfalse: ff exists: x:A. B[x] or: P ∨ Q sq_type: SQType(T) guard: {T} bnot: ¬bb assert: b false: False squash: T not: ¬A iff: ⇐⇒ Q true: True rev_implies:  Q cand: c∧ B
Lemmas referenced :  list_induction equal_wf list_wf filter_wf5 reduce_wf insert_wf subtype_rel_dep_function bool_wf l_member_wf subtype_rel_self set_wf reduce_nil_lemma filter_nil_lemma reduce_cons_lemma filter_cons_lemma eqtt_to_assert eqff_to_assert bool_cases_sqequal subtype_base_sq bool_subtype_base assert-bnot deq_wf insert-cases2 squash_wf true_wf ite_rw_false cons_wf member_filter_2 assert_wf iff_weakening_equal member_filter
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation introduction cut lambdaFormation thin extract_by_obid sqequalHypSubstitution isectElimination hypothesisEquality sqequalRule lambdaEquality cumulativity hypothesis because_Cache applyEquality setEquality independent_isectElimination setElimination rename independent_functionElimination dependent_functionElimination isect_memberEquality voidElimination voidEquality functionExtensionality unionElimination equalityElimination equalityTransitivity equalitySymmetry productElimination dependent_pairFormation promote_hyp instantiate functionEquality axiomEquality universeEquality hyp_replacement applyLambdaEquality imageElimination equalityUniverse levelHypothesis natural_numberEquality imageMemberEquality baseClosed independent_pairFormation

Latex:
\mforall{}[T:Type]
    \mforall{}eq:EqDecider(T).  \mforall{}as,bs:T  List.  \mforall{}P:T  {}\mrightarrow{}  \mBbbB{}.    (filter(P;as  \mcup{}  bs)  =  filter(P;as)  \mcup{}  filter(P;bs))



Date html generated: 2017_04_17-AM-09_09_50
Last ObjectModification: 2017_02_27-PM-05_17_56

Theory : decidable!equality


Home Index