Nuprl Lemma : filter-le

[T:Type]. ∀[P:T ⟶ 𝔹]. ∀[L:T List].  (||filter(P;L)|| ≤ ||L||)


Proof




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

Latex:
\mforall{}[T:Type].  \mforall{}[P:T  {}\mrightarrow{}  \mBbbB{}].  \mforall{}[L:T  List].    (||filter(P;L)||  \mleq{}  ||L||)



Date html generated: 2017_04_17-AM-08_36_25
Last ObjectModification: 2017_02_27-PM-04_55_12

Theory : list_1


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