Nuprl Lemma : member_filter2

[T:Type]. ∀L:T List. ∀P:ℕ||L|| ⟶ 𝔹. ∀x:T.  ((x ∈ filter2(P;L)) ⇐⇒ ∃i:ℕ||L||. ((x L[i] ∈ T) ∧ (↑(P i))))


Proof




Definitions occuring in Statement :  filter2: filter2(P;L) l_member: (x ∈ l) select: L[n] length: ||as|| list: List int_seg: {i..j-} assert: b bool: 𝔹 uall: [x:A]. B[x] all: x:A. B[x] exists: x:A. B[x] iff: ⇐⇒ Q and: P ∧ Q apply: a function: x:A ⟶ B[x] natural_number: $n universe: Type equal: t ∈ T
Definitions unfolded in proof :  uall: [x:A]. B[x] all: x:A. B[x] member: t ∈ T so_lambda: λ2x.t[x] prop: and: P ∧ Q int_seg: {i..j-} uimplies: supposing a guard: {T} lelt: i ≤ j < k 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 less_than: a < b squash: T so_apply: x[s] select: L[n] nil: [] it: so_lambda: λ2y.t[x; y] so_apply: x[s1;s2] iff: ⇐⇒ Q rev_implies:  Q l_member: (x ∈ l) cand: c∧ B nat: ge: i ≥  le: A ≤ B less_than': less_than'(a;b) nat_plus: + true: True uiff: uiff(P;Q) bool: 𝔹 unit: Unit btrue: tt ifthenelse: if then else fi  bfalse: ff subtype_rel: A ⊆B sq_type: SQType(T) subtract: m cons: [a b]
Lemmas referenced :  list_induction all_wf int_seg_wf length_wf bool_wf iff_wf l_member_wf filter2_wf exists_wf equal_wf select_wf int_seg_properties decidable__le full-omega-unsat intformand_wf intformnot_wf intformle_wf itermConstant_wf itermVar_wf istype-int int_formula_prop_and_lemma istype-void 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 assert_wf istype-universe length_of_nil_lemma filter2_nil_lemma stuck-spread istype-base length_of_cons_lemma list_wf nat_properties nat_wf less_than_wf istype-false add_nat_plus length_wf_nat nat_plus_properties add-is-int-iff itermAdd_wf intformeq_wf int_term_value_add_lemma int_formula_prop_eq_lemma false_wf le_wf equal-wf-T-base bnot_wf not_wf eqtt_to_assert uiff_transitivity eqff_to_assert assert_of_bnot squash_wf true_wf cons_filter2 subtype_rel_self iff_weakening_equal cons_wf non_neg_length decidable__equal_int subtype_base_sq int_subtype_base add-member-int_seg2 subtract_wf itermSubtract_wf int_term_value_subtract_lemma select_cons_tl select-cons-tl add-subtract-cancel select-cons-hd subtract-add-cancel
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation_alt lambdaFormation_alt cut thin introduction extract_by_obid sqequalHypSubstitution isectElimination hypothesisEquality sqequalRule lambdaEquality_alt functionEquality natural_numberEquality hypothesis because_Cache productEquality setElimination rename independent_isectElimination productElimination dependent_functionElimination unionElimination approximateComputation independent_functionElimination dependent_pairFormation_alt int_eqEquality isect_memberEquality_alt voidElimination independent_pairFormation universeIsType imageElimination applyEquality functionIsType baseClosed inhabitedIsType productIsType equalityIsType1 universeEquality dependent_set_memberEquality_alt imageMemberEquality equalityTransitivity equalitySymmetry applyLambdaEquality pointwiseFunctionality promote_hyp baseApply closedConclusion addEquality equalityElimination instantiate cumulativity intEquality

Latex:
\mforall{}[T:Type]
    \mforall{}L:T  List.  \mforall{}P:\mBbbN{}||L||  {}\mrightarrow{}  \mBbbB{}.  \mforall{}x:T.    ((x  \mmember{}  filter2(P;L))  \mLeftarrow{}{}\mRightarrow{}  \mexists{}i:\mBbbN{}||L||.  ((x  =  L[i])  \mwedge{}  (\muparrow{}(P  i))))



Date html generated: 2019_10_15-AM-10_55_05
Last ObjectModification: 2018_10_09-AM-10_21_29

Theory : list!


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