Nuprl Lemma : ml-length-sq
∀[T:Type]. ∀[l:T List]. (ml-length(l) ~ ||l||) supposing valueall-type(T)
Proof
Definitions occuring in Statement : 
ml-length: ml-length(l)
, 
length: ||as||
, 
list: T List
, 
valueall-type: valueall-type(T)
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
universe: Type
, 
sqequal: s ~ t
Definitions unfolded in proof : 
ml-length: ml-length(l)
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
all: ∀x:A. B[x]
, 
nat: ℕ
, 
implies: P 
⇒ Q
, 
false: False
, 
ge: i ≥ j 
, 
guard: {T}
, 
prop: ℙ
, 
or: P ∨ Q
, 
ml_apply: f(x)
, 
spreadcons: spreadcons, 
callbyvalueall: callbyvalueall, 
evalall: evalall(t)
, 
nil: []
, 
it: ⋅
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
cons: [a / b]
, 
top: Top
, 
le: A ≤ B
, 
and: P ∧ Q
, 
less_than': less_than'(a;b)
, 
not: ¬A
, 
colength: colength(L)
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
sq_type: SQType(T)
, 
less_than: a < b
, 
squash: ↓T
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
sq_stable: SqStable(P)
, 
subtract: n - m
, 
subtype_rel: A ⊆r B
, 
has-value: (a)↓
, 
has-valueall: has-valueall(a)
, 
bfalse: ff
Lemmas referenced : 
nat_properties, 
less_than_transitivity1, 
less_than_irreflexivity, 
ge_wf, 
less_than_wf, 
list-cases, 
null_nil_lemma, 
length_of_nil_lemma, 
product_subtype_list, 
colength-cons-not-zero, 
istype-void, 
colength_wf_list, 
istype-false, 
le_wf, 
subtract-1-ge-0, 
subtype_base_sq, 
nat_wf, 
set_subtype_base, 
int_subtype_base, 
spread_cons_lemma, 
sq_stable__le, 
add-associates, 
istype-int, 
add-commutes, 
add-swap, 
zero-add, 
length_of_cons_lemma, 
valueall-type-has-valueall, 
list_wf, 
list-valueall-type, 
cons_wf, 
evalall-reduce, 
null_cons_lemma, 
length_wf, 
le_weakening2, 
valueall-type_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
Error :isect_memberFormation_alt, 
introduction, 
cut, 
thin, 
Error :lambdaFormation_alt, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
natural_numberEquality, 
independent_isectElimination, 
independent_functionElimination, 
voidElimination, 
Error :universeIsType, 
Error :lambdaEquality_alt, 
dependent_functionElimination, 
axiomSqEquality, 
Error :functionIsTypeImplies, 
Error :inhabitedIsType, 
unionElimination, 
callbyvalueReduce, 
sqleReflexivity, 
promote_hyp, 
hypothesis_subsumption, 
productElimination, 
Error :isect_memberEquality_alt, 
Error :equalityIsType1, 
because_Cache, 
Error :dependent_set_memberEquality_alt, 
independent_pairFormation, 
instantiate, 
cumulativity, 
intEquality, 
equalityTransitivity, 
equalitySymmetry, 
imageElimination, 
imageMemberEquality, 
baseClosed, 
applyLambdaEquality, 
applyEquality, 
minusEquality, 
Error :equalityIsType4, 
baseApply, 
closedConclusion, 
addEquality, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[l:T  List].  (ml-length(l)  \msim{}  ||l||)  supposing  valueall-type(T)
Date html generated:
2019_06_20-PM-00_44_27
Last ObjectModification:
2018_10_07-AM-00_35_09
Theory : ML
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