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: List assert: b bool: 𝔹 less_than: a < b uimplies: supposing a uall: [x:A]. B[x] exists: x:A. B[x] not: ¬A and: P ∧ Q apply: 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: supposing a prop: and: P ∧ Q so_apply: x[s] exists: x:A. B[x] subtype_rel: A ⊆B all: x:A. B[x] implies:  Q top: Top iff: ⇐⇒ Q false: False or: P ∨ Q bool: 𝔹 unit: Unit it: btrue: tt uiff: uiff(P;Q) ifthenelse: if then else 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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