Nuprl Lemma : select_nth_tl
∀[T:Type]. ∀[as:T List]. ∀[n:{0...||as||}]. ∀[i:ℕ||as|| - n].  (nth_tl(n;as)[i] = as[i + n] ∈ T)
Proof
Definitions occuring in Statement : 
select: L[n]
, 
length: ||as||
, 
nth_tl: nth_tl(n;as)
, 
list: T List
, 
int_iseg: {i...j}
, 
int_seg: {i..j-}
, 
uall: ∀[x:A]. B[x]
, 
subtract: n - m
, 
add: n + m
, 
natural_number: $n
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
so_lambda: λ2x.t[x]
, 
int_iseg: {i...j}
, 
int_seg: {i..j-}
, 
uimplies: b supposing a
, 
guard: {T}
, 
and: P ∧ Q
, 
lelt: i ≤ j < k
, 
all: ∀x:A. B[x]
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
false: False
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
top: Top
, 
prop: ℙ
, 
squash: ↓T
, 
true: True
, 
subtype_rel: A ⊆r B
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
le: A ≤ B
, 
so_apply: x[s]
, 
nth_tl: nth_tl(n;as)
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
ifthenelse: if b then t else f fi 
, 
bfalse: ff
, 
sq_type: SQType(T)
, 
cand: A c∧ B
, 
ge: i ≥ j 
, 
less_than: a < b
, 
subtract: n - m
Lemmas referenced : 
list_induction, 
uall_wf, 
int_iseg_wf, 
length_wf, 
int_seg_wf, 
subtract_wf, 
equal_wf, 
select_wf, 
nth_tl_wf, 
int_seg_properties, 
int_iseg_properties, 
decidable__le, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
less_than_wf, 
squash_wf, 
true_wf, 
length_nth_tl, 
iff_weakening_equal, 
decidable__lt, 
intformless_wf, 
itermSubtract_wf, 
int_formula_prop_less_lemma, 
int_term_value_subtract_lemma, 
itermAdd_wf, 
int_term_value_add_lemma, 
list_wf, 
length_of_nil_lemma, 
nil_wf, 
length_of_cons_lemma, 
cons_wf, 
le_int_wf, 
bool_wf, 
equal-wf-T-base, 
assert_wf, 
le_wf, 
lt_int_wf, 
bnot_wf, 
uiff_transitivity, 
eqtt_to_assert, 
assert_of_le_int, 
eqff_to_assert, 
assert_functionality_wrt_uiff, 
bnot_of_le_int, 
assert_of_lt_int, 
reduce_tl_cons_lemma, 
subtype_base_sq, 
int_subtype_base, 
decidable__equal_int, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
add-zero, 
add-is-int-iff, 
false_wf, 
non_neg_length, 
lelt_wf, 
select_cons_tl, 
add-commutes, 
add-swap, 
add-associates
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
thin, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
natural_numberEquality, 
cumulativity, 
hypothesis, 
because_Cache, 
setElimination, 
rename, 
independent_isectElimination, 
productElimination, 
dependent_functionElimination, 
unionElimination, 
dependent_pairFormation, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
applyEquality, 
imageElimination, 
equalityTransitivity, 
equalitySymmetry, 
imageMemberEquality, 
baseClosed, 
universeEquality, 
independent_functionElimination, 
addEquality, 
axiomEquality, 
lambdaFormation, 
equalityElimination, 
instantiate, 
productEquality, 
pointwiseFunctionality, 
promote_hyp, 
baseApply, 
closedConclusion, 
dependent_set_memberEquality, 
minusEquality
Latex:
\mforall{}[T:Type].  \mforall{}[as:T  List].  \mforall{}[n:\{0...||as||\}].  \mforall{}[i:\mBbbN{}||as||  -  n].    (nth\_tl(n;as)[i]  =  as[i  +  n])
Date html generated:
2017_04_14-AM-09_25_37
Last ObjectModification:
2017_02_27-PM-04_00_06
Theory : list_1
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