Nuprl Lemma : nth_tl_wf

[A:Type]. ∀[as:A List]. ∀[i:ℤ].  (nth_tl(i;as) ∈ List)


Proof




Definitions occuring in Statement :  nth_tl: nth_tl(n;as) list: List uall: [x:A]. B[x] member: t ∈ T int: universe: Type
Definitions unfolded in proof :  uall: [x:A]. B[x] member: t ∈ T all: x:A. B[x] ge: i ≥  decidable: Dec(P) or: P ∨ Q subtype_rel: A ⊆B nat: prop: implies:  Q false: False guard: {T} uimplies: supposing a nth_tl: nth_tl(n;as) le_int: i ≤j lt_int: i <j bnot: ¬bb ifthenelse: if then else fi  bfalse: ff subtract: m btrue: tt iff: ⇐⇒ Q and: P ∧ Q not: ¬A rev_implies:  Q uiff: uiff(P;Q) top: Top le: A ≤ B less_than': less_than'(a;b) true: True bool: 𝔹 unit: Unit it: exists: x:A. B[x] sq_type: SQType(T) assert: b
Lemmas referenced :  list_wf decidable__le nat_wf le_wf nat_properties less_than_transitivity1 less_than_irreflexivity ge_wf less_than_wf subtract_wf false_wf not-ge-2 less-iff-le condition-implies-le minus-one-mul zero-add minus-one-mul-top minus-add minus-minus add-associates add-swap add-commutes add_functionality_wrt_le add-zero le-add-cancel le_int_wf bool_wf eqff_to_assert equal_wf bool_cases_sqequal subtype_base_sq bool_subtype_base assert-bnot assert_of_le_int tl_wf not-le-2 minus-zero
Rules used in proof :  sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity isect_memberFormation introduction cut sqequalHypSubstitution hypothesis sqequalRule axiomEquality equalityTransitivity equalitySymmetry intEquality isect_memberEquality isectElimination thin hypothesisEquality because_Cache extract_by_obid cumulativity universeEquality dependent_functionElimination natural_numberEquality unionElimination hypothesis_subsumption lambdaEquality setElimination rename dependent_set_memberEquality intWeakElimination lambdaFormation independent_isectElimination independent_functionElimination voidElimination independent_pairFormation productElimination addEquality applyEquality voidEquality minusEquality equalityElimination dependent_pairFormation promote_hyp instantiate

Latex:
\mforall{}[A:Type].  \mforall{}[as:A  List].  \mforall{}[i:\mBbbZ{}].    (nth\_tl(i;as)  \mmember{}  A  List)



Date html generated: 2017_04_14-AM-08_34_25
Last ObjectModification: 2017_02_27-PM-03_22_08

Theory : list_0


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