Nuprl Lemma : nth_tl_wf
∀[A:Type]. ∀[as:A List]. ∀[i:ℤ].  (nth_tl(i;as) ∈ A List)
Proof
Definitions occuring in Statement : 
nth_tl: nth_tl(n;as), 
list: T List, 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
int: ℤ, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
all: ∀x:A. B[x], 
ge: i ≥ j , 
decidable: Dec(P), 
or: P ∨ Q, 
subtype_rel: A ⊆r B, 
nat: ℕ, 
prop: ℙ, 
implies: P ⇒ Q, 
false: False, 
guard: {T}, 
uimplies: b supposing a, 
nth_tl: nth_tl(n;as), 
le_int: i ≤z j, 
lt_int: i <z j, 
bnot: ¬bb, 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
subtract: n - m, 
btrue: tt, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
not: ¬A, 
rev_implies: P ⇐ 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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