Nuprl Lemma : filter-less

∀[T:Type]. ∀[P:T ⟶ 𝔹]. ∀[L:T List].  ||filter(P;L)|| < ||L|| supposing ∃x:T. ((x ∈ L) ∧ (¬↑(P x)))


Proof




Definitions occuring in Statement :  l_member: (x ∈ l),  length: ||as||,  filter: filter(P;l),  list: T List,  assert: ↑b,  bool: 𝔹,  less_than: a < b,  uimplies: b supposing a,  uall: ∀[x:A]. B[x],  exists: ∃x:A. B[x],  not: ¬A,  and: P ∧ Q,  apply: f a,  function: x:A ⟶ B[x],  universe: Type
Definitions unfolded in proof :  uall: ∀[x:A]. B[x],  member: t ∈ T,  so_lambda: λ2x.t[x],  uimplies: b supposing a,  prop: ℙ,  and: P ∧ Q,  so_apply: x[s],  exists: ∃x:A. B[x],  subtype_rel: A ⊆r B,  all: ∀x:A. B[x],  implies: P ⇒ Q,  top: Top,  iff: P ⇐⇒ Q,  false: False,  or: P ∨ Q,  bool: 𝔹,  unit: Unit,  it: ⋅,  btrue: tt,  uiff: uiff(P;Q),  ifthenelse: if b then t else f fi ,  not: ¬A,  bfalse: ff,  sq_type: SQType(T),  guard: {T},  bnot: ¬bb,  assert: ↑b,  decidable: Dec(P),  le: A ≤ B,  satisfiable_int_formula: satisfiable_int_formula(fmla),  less_than: a < b,  squash: ↓T
Lemmas referenced :  list_induction,  isect_wf,  exists_wf,  l_member_wf,  not_wf,  assert_wf,  less_than_wf,  length_wf,  filter_wf5,  subtype_rel_dep_function,  bool_wf,  subtype_rel_self,  set_wf,  list_wf,  filter_nil_lemma,  length_of_nil_lemma,  nil_wf,  filter_cons_lemma,  length_of_cons_lemma,  cons_wf,  member-less_than,  nil_member,  cons_member,  eqtt_to_assert,  assert_elim,  and_wf,  equal_wf,  not_assert_elim,  btrue_neq_bfalse,  eqff_to_assert,  bool_cases_sqequal,  subtype_base_sq,  bool_subtype_base,  assert-bnot,  filter-le,  decidable__lt,  satisfiable-full-omega-tt,  intformand_wf,  intformnot_wf,  intformless_wf,  itermVar_wf,  itermAdd_wf,  itermConstant_wf,  intformle_wf,  int_formula_prop_and_lemma,  int_formula_prop_not_lemma,  int_formula_prop_less_lemma,  int_term_value_var_lemma,  int_term_value_add_lemma,  int_term_value_constant_lemma,  int_formula_prop_le_lemma,  int_formula_prop_wf
Rules used in proof :  sqequalSubstitution,  sqequalTransitivity,  computationStep,  sqequalReflexivity,  isect_memberFormation,  introduction,  cut,  thin,  extract_by_obid,  sqequalHypSubstitution,  isectElimination,  hypothesisEquality,  sqequalRule,  lambdaEquality,  cumulativity,  productEquality,  because_Cache,  hypothesis,  applyEquality,  functionExtensionality,  setEquality,  independent_isectElimination,  setElimination,  rename,  lambdaFormation,  independent_functionElimination,  dependent_functionElimination,  isect_memberEquality,  voidElimination,  voidEquality,  productElimination,  equalityTransitivity,  equalitySymmetry,  functionEquality,  universeEquality,  unionElimination,  equalityElimination,  dependent_set_memberEquality,  independent_pairFormation,  applyLambdaEquality,  dependent_pairFormation,  promote_hyp,  instantiate,  addEquality,  natural_numberEquality,  int_eqEquality,  intEquality,  computeAll,  imageElimination

Latex:
\mforall{}[T:Type].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[L:T  List].    ||filter(P;L)||  <  ||L||  supposing  \mexists{}x:T.  ((x  \mmember{}  L)  \mwedge{}  (\mneg{}\muparrow{}(P  x)))



Date html generated: 2017_04_17-AM-08_36_41
Last ObjectModification: 2017_02_27-PM-04_55_31

Theory : list_1


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