Nuprl Lemma : bag-extensionality
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[as,bs:bag(T)].  uiff(as = bs ∈ bag(T);∀x:T. ((#x in as) = (#x in bs) ∈ ℤ))
Proof
Definitions occuring in Statement : 
bag-count: (#x in bs)
, 
bag: bag(T)
, 
deq: EqDecider(T)
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
int: ℤ
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
uimplies: b supposing a
, 
all: ∀x:A. B[x]
, 
squash: ↓T
, 
prop: ℙ
, 
true: True
, 
subtype_rel: A ⊆r B
, 
nat: ℕ
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
implies: P 
⇒ Q
, 
bag: bag(T)
, 
quotient: x,y:A//B[x; y]
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
istype: istype(T)
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
bag-size: #(bs)
, 
eqof: eqof(d)
, 
bag-filter: [x∈b|p[x]]
, 
deq: EqDecider(T)
Lemmas referenced : 
equal_wf, 
squash_wf, 
true_wf, 
istype-universe, 
bag-count_wf, 
bag_wf, 
deq_wf, 
nat_wf, 
subtype_rel_self, 
iff_weakening_equal, 
list_wf, 
permutation_wf, 
permutation_weakening, 
quotient-member-eq, 
permutation-equiv, 
list-subtype-bag, 
istype-int, 
set_subtype_base, 
le_wf, 
int_subtype_base, 
permutation-iff-count, 
filter_functionality, 
eta_conv, 
bool_wf, 
length_wf, 
filter_wf5, 
subtype_rel_dep_function, 
l_member_wf, 
bag-count-sqequal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
independent_pairFormation, 
lambdaFormation_alt, 
applyEquality, 
thin, 
lambdaEquality_alt, 
sqequalHypSubstitution, 
imageElimination, 
extract_by_obid, 
isectElimination, 
hypothesisEquality, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
universeIsType, 
inhabitedIsType, 
universeEquality, 
intEquality, 
natural_numberEquality, 
sqequalRule, 
imageMemberEquality, 
baseClosed, 
setElimination, 
rename, 
because_Cache, 
instantiate, 
independent_isectElimination, 
productElimination, 
independent_functionElimination, 
dependent_functionElimination, 
axiomEquality, 
functionIsTypeImplies, 
equalityIsType1, 
promote_hyp, 
pointwiseFunctionality, 
pertypeElimination, 
productIsType, 
equalityIsType4, 
functionIsType, 
closedConclusion, 
independent_pairEquality, 
isect_memberEquality_alt, 
hyp_replacement, 
setEquality, 
setIsType
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[as,bs:bag(T)].    uiff(as  =  bs;\mforall{}x:T.  ((\#x  in  as)  =  (\#x  in  bs)))
Date html generated:
2019_10_16-AM-11_30_35
Last ObjectModification:
2018_10_11-PM-07_08_11
Theory : bags_2
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