Nuprl Lemma : filter_is_empty

[T:Type]. ∀[P:T ⟶ 𝔹]. ∀[L:T List].  uiff(↑null(filter(P;L));∀[i:ℕ||L||]. (¬↑(P L[i])))


Proof




Definitions occuring in Statement :  select: L[n] length: ||as|| null: null(as) filter: filter(P;l) list: List int_seg: {i..j-} assert: b bool: 𝔹 uiff: uiff(P;Q) uall: [x:A]. B[x] not: ¬A apply: a function: x:A ⟶ B[x] natural_number: $n universe: Type
Definitions unfolded in proof :  member: t ∈ T uall: [x:A]. B[x] int_seg: {i..j-} uimplies: supposing a guard: {T} lelt: i ≤ j < k and: P ∧ Q all: x:A. B[x] decidable: Dec(P) or: P ∨ Q not: ¬A implies:  Q satisfiable_int_formula: satisfiable_int_formula(fmla) exists: x:A. B[x] false: False top: Top prop: less_than: a < b squash: T subtype_rel: A ⊆B so_lambda: λ2x.t[x] so_apply: x[s] uiff: uiff(P;Q) assert: b ifthenelse: if then else fi  btrue: tt bfalse: ff true: True iff: ⇐⇒ Q rev_implies:  Q bool: 𝔹 unit: Unit it: l_all: (∀x∈L.P[x])
Lemmas referenced :  assert_wf select_wf int_seg_properties length_wf decidable__le full-omega-unsat intformand_wf intformnot_wf intformle_wf itermConstant_wf itermVar_wf int_formula_prop_and_lemma int_formula_prop_not_lemma int_formula_prop_le_lemma int_term_value_constant_lemma int_term_value_var_lemma int_formula_prop_wf decidable__lt intformless_wf int_formula_prop_less_lemma int_seg_wf null_wf filter_wf5 subtype_rel_dep_function bool_wf l_member_wf subtype_rel_self set_wf uall_wf not_wf list_wf assert_witness null_cons_lemma false_wf true_wf l_all_wf equal-wf-T-base bnot_wf list_induction iff_wf filter_nil_lemma null_nil_lemma l_all_nil l_all_wf_nil filter_cons_lemma eqtt_to_assert uiff_transitivity eqff_to_assert assert_of_bnot equal_wf l_all_cons ifthenelse_wf cons_wf satisfiable-full-omega-tt
Rules used in proof :  cut sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity introduction extract_by_obid sqequalHypSubstitution isectElimination thin applyEquality functionExtensionality hypothesisEquality cumulativity because_Cache setElimination rename hypothesis independent_isectElimination natural_numberEquality productElimination dependent_functionElimination unionElimination approximateComputation independent_functionElimination dependent_pairFormation lambdaEquality int_eqEquality intEquality isect_memberEquality voidElimination voidEquality sqequalRule independent_pairFormation imageElimination setEquality lambdaFormation functionEquality universeEquality isect_memberFormation independent_pairEquality equalityTransitivity equalitySymmetry productEquality baseClosed equalityElimination computeAll

Latex:
\mforall{}[T:Type].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[L:T  List].    uiff(\muparrow{}null(filter(P;L));\mforall{}[i:\mBbbN{}||L||].  (\mneg{}\muparrow{}(P  L[i])))



Date html generated: 2019_06_20-PM-01_25_50
Last ObjectModification: 2018_09_17-PM-10_26_04

Theory : list_1


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