Nuprl Lemma : select_tl
∀[A:Type]. ∀[as:A List]. ∀[n:ℕ||as|| - 1].  (tl(as)[n] = as[n + 1] ∈ A)
Proof
Definitions occuring in Statement : 
select: L[n]
, 
length: ||as||
, 
tl: tl(l)
, 
list: T List
, 
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_seg: {i..j-}
, 
uimplies: b supposing a
, 
sq_stable: SqStable(P)
, 
implies: P 
⇒ Q
, 
lelt: i ≤ j < k
, 
and: P ∧ Q
, 
squash: ↓T
, 
prop: ℙ
, 
all: ∀x:A. B[x]
, 
ge: i ≥ j 
, 
decidable: Dec(P)
, 
or: P ∨ Q
, 
iff: P 
⇐⇒ Q
, 
not: ¬A
, 
rev_implies: P 
⇐ Q
, 
false: False
, 
uiff: uiff(P;Q)
, 
subtract: n - m
, 
subtype_rel: A ⊆r B
, 
top: Top
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
true: True
, 
guard: {T}
, 
so_apply: x[s]
, 
select: L[n]
, 
nil: []
, 
it: ⋅
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
Lemmas referenced : 
add-subtract-cancel, 
select-cons-tl, 
reduce_tl_cons_lemma, 
length_of_cons_lemma, 
le-add-cancel2, 
base_wf, 
stuck-spread, 
reduce_tl_nil_lemma, 
length_of_nil_lemma, 
list_wf, 
not-lt-2, 
decidable__lt, 
add-zero, 
not-le-2, 
iff_weakening_equal, 
le-add-cancel, 
add_functionality_wrt_le, 
zero-add, 
add-commutes, 
minus-one-mul-top, 
add-swap, 
minus-one-mul, 
minus-add, 
add-associates, 
condition-implies-le, 
less-iff-le, 
not-ge-2, 
false_wf, 
decidable__le, 
length_tl, 
true_wf, 
squash_wf, 
less_than_wf, 
sq_stable__le, 
tl_wf, 
select_wf, 
equal_wf, 
length_wf, 
subtract_wf, 
int_seg_wf, 
uall_wf, 
list_induction
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
thin, 
lemma_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
sqequalRule, 
lambdaEquality, 
natural_numberEquality, 
cumulativity, 
hypothesis, 
because_Cache, 
setElimination, 
rename, 
independent_isectElimination, 
independent_functionElimination, 
productElimination, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
applyEquality, 
equalityTransitivity, 
equalitySymmetry, 
intEquality, 
dependent_functionElimination, 
unionElimination, 
independent_pairFormation, 
lambdaFormation, 
voidElimination, 
addEquality, 
minusEquality, 
isect_memberEquality, 
voidEquality, 
universeEquality, 
axiomEquality
Latex:
\mforall{}[A:Type].  \mforall{}[as:A  List].  \mforall{}[n:\mBbbN{}||as||  -  1].    (tl(as)[n]  =  as[n  +  1])
Date html generated:
2016_05_14-AM-06_36_37
Last ObjectModification:
2016_01_06-PM-08_33_28
Theory : list_0
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