Nuprl Lemma : length_segment
∀[T:Type]. ∀[as:T List]. ∀[i:{0...||as||}]. ∀[j:{i...||as||}].  (||as[i..j-]|| = (j - i) ∈ ℤ)
Proof
Definitions occuring in Statement : 
segment: as[m..n-]
, 
length: ||as||
, 
list: T List
, 
int_iseg: {i...j}
, 
uall: ∀[x:A]. B[x]
, 
subtract: n - m
, 
natural_number: $n
, 
int: ℤ
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
, 
int_iseg: {i...j}
, 
segment: as[m..n-]
, 
and: P ∧ Q
, 
cand: A c∧ B
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
exists: ∃x:A. B[x]
, 
subtype_rel: A ⊆r B
, 
nat: ℕ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
uimplies: b supposing a
, 
prop: ℙ
, 
squash: ↓T
, 
true: True
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
le: A ≤ B
, 
subtract: n - m
, 
top: Top
, 
uiff: uiff(P;Q)
, 
nat_plus: ℕ+
, 
less_than: a < b
, 
less_than': less_than'(a;b)
, 
not: ¬A
, 
false: False
, 
decidable: Dec(P)
, 
or: P ∨ Q
Lemmas referenced : 
int_iseg_wf, 
length_wf, 
list_wf, 
length_firstn, 
nth_tl_wf, 
subtract_wf, 
non_neg_length, 
length_wf_nat, 
nat_wf, 
set_subtype_base, 
le_wf, 
int_subtype_base, 
equal_wf, 
squash_wf, 
true_wf, 
length_nth_tl, 
iff_weakening_equal, 
minus-one-mul, 
add-commutes, 
not-le-2, 
add_functionality_wrt_le, 
le_reflexive, 
minus-one-mul-top, 
add-associates, 
minus-zero, 
add-zero, 
one-mul, 
zero-add, 
add-swap, 
add-mul-special, 
zero-mul, 
two-mul, 
mul-distributes-right, 
omega-shadow, 
less_than_wf, 
mul-distributes, 
mul-associates, 
le-add-cancel, 
add-is-int-iff, 
minus-add, 
mul-commutes, 
le-add-cancel-alt, 
int_iseg_properties, 
nat_properties, 
decidable__le
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
setElimination, 
rename, 
hypothesisEquality, 
hypothesis, 
cumulativity, 
because_Cache, 
natural_numberEquality, 
universeEquality, 
isect_memberFormation, 
sqequalRule, 
isect_memberEquality, 
axiomEquality, 
dependent_set_memberEquality, 
lambdaFormation, 
dependent_pairFormation, 
sqequalIntensionalEquality, 
applyEquality, 
intEquality, 
lambdaEquality, 
independent_isectElimination, 
equalityTransitivity, 
equalitySymmetry, 
dependent_functionElimination, 
independent_functionElimination, 
productElimination, 
promote_hyp, 
independent_pairFormation, 
imageElimination, 
imageMemberEquality, 
baseClosed, 
productEquality, 
voidElimination, 
voidEquality, 
addEquality, 
multiplyEquality, 
minusEquality, 
baseApply, 
closedConclusion, 
unionElimination
Latex:
\mforall{}[T:Type].  \mforall{}[as:T  List].  \mforall{}[i:\{0...||as||\}].  \mforall{}[j:\{i...||as||\}].    (||as[i..j\msupminus{}]||  =  (j  -  i))
Date html generated:
2017_04_14-AM-08_47_46
Last ObjectModification:
2017_02_27-PM-03_34_47
Theory : list_0
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