Nuprl Lemma : list_extensionality
∀[T:Type]. ∀[a,b:T List].
  (a = b ∈ (T List)) supposing ((∀i:ℕ. (i < ||a|| ⇒ (a[i] = b[i] ∈ T))) and (||a|| = ||b|| ∈ ℤ))
Proof
Definitions occuring in Statement : 
select: L[n], 
length: ||as||, 
list: T List, 
nat: ℕ, 
less_than: a < b, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
int: ℤ, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
so_apply: x[s], 
all: ∀x:A. B[x], 
guard: {T}, 
squash: ↓T, 
sq_stable: SqStable(P), 
uimplies: b supposing a, 
nat: ℕ, 
prop: ℙ, 
implies: P ⇒ Q, 
so_lambda: λ2x.t[x], 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
select: L[n], 
nil: [], 
it: ⋅, 
so_lambda: λ2x y.t[x; y], 
top: Top, 
so_apply: x[s1;s2], 
exists: ∃x:A. B[x], 
subtype_rel: A ⊆r B, 
false: False, 
subtract: n - m, 
sq_type: SQType(T), 
ge: i ≥ j , 
le: A ≤ B, 
and: P ∧ Q, 
less_than': less_than'(a;b), 
true: True, 
not: ¬A, 
cons: [a / b], 
less_than: a < b, 
nat_plus: ℕ+, 
uiff: uiff(P;Q), 
rev_implies: P ⇐ Q, 
iff: P ⇐⇒ Q, 
or: P ∨ Q, 
decidable: Dec(P)
Lemmas referenced : 
list_wf, 
le_weakening, 
length_wf, 
less_than_transitivity1, 
sq_stable__le, 
select_wf, 
equal_wf, 
less_than_wf, 
nat_wf, 
all_wf, 
list_induction, 
equal-wf-base-T, 
nil_wf, 
length_of_nil_lemma, 
stuck-spread, 
base_wf, 
equal-wf-base, 
length_of_cons_lemma, 
non_neg_length, 
length_wf_nat, 
set_subtype_base, 
le_wf, 
int_subtype_base, 
cons_wf, 
less_than_irreflexivity, 
equal-wf-T-base, 
add-commutes, 
subtract_wf, 
minus-add, 
add-associates, 
minus-one-mul, 
zero-add, 
add-swap, 
add-mul-special, 
two-mul, 
mul-distributes-right, 
zero-mul, 
add-zero, 
one-mul, 
subtype_base_sq, 
minus-zero, 
nat_properties, 
and_wf, 
true_wf, 
squash_wf, 
nat_plus_wf, 
add_nat_plus, 
false_wf, 
le-add-cancel2, 
add_functionality_wrt_le, 
minus-one-mul-top, 
condition-implies-le, 
le_antisymmetry_iff, 
not-equal-2, 
decidable__int_equal, 
less-iff-le, 
not-lt-2, 
decidable__lt, 
le-add-cancel, 
not-le-2, 
decidable__le, 
iff_weakening_equal, 
select_cons_tl
Rules used in proof : 
axiomEquality, 
isect_memberEquality, 
isect_memberFormation, 
universeEquality, 
intEquality, 
dependent_functionElimination, 
imageElimination, 
baseClosed, 
imageMemberEquality, 
independent_functionElimination, 
natural_numberEquality, 
independent_isectElimination, 
hypothesisEquality, 
cumulativity, 
equalitySymmetry, 
equalityTransitivity, 
because_Cache, 
rename, 
setElimination, 
functionEquality, 
lambdaEquality, 
sqequalRule, 
hypothesis, 
thin, 
isectElimination, 
sqequalHypSubstitution, 
extract_by_obid, 
introduction, 
cut, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution, 
lambdaFormation, 
voidEquality, 
voidElimination, 
dependent_pairFormation, 
sqequalIntensionalEquality, 
applyEquality, 
productElimination, 
promote_hyp, 
addEquality, 
minusEquality, 
multiplyEquality, 
instantiate, 
hyp_replacement, 
dependent_set_memberEquality, 
independent_pairFormation, 
applyLambdaEquality, 
unionElimination
Latex:
\mforall{}[T:Type].  \mforall{}[a,b:T  List].
    (a  =  b)  supposing  ((\mforall{}i:\mBbbN{}.  (i  <  ||a||  {}\mRightarrow{}  (a[i]  =  b[i])))  and  (||a||  =  ||b||))
Date html generated:
2019_06_20-PM-00_41_09
Last ObjectModification:
2018_08_06-PM-02_09_12
Theory : list_0
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