Nuprl Lemma : bag-append-eq-empty
∀[T:Type]. ∀[b1,b2:bag(T)].  uiff((b1 + b2) = {} ∈ bag(T);(b1 = {} ∈ bag(T)) ∧ (b2 = {} ∈ bag(T)))
Proof
Definitions occuring in Statement : 
bag-append: as + bs
, 
empty-bag: {}
, 
bag: bag(T)
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
and: P ∧ Q
, 
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
, 
subtype_rel: A ⊆r B
, 
all: ∀x:A. B[x]
, 
empty-bag: {}
, 
bag-append: as + bs
, 
top: Top
, 
guard: {T}
, 
implies: P 
⇒ Q
, 
prop: ℙ
Lemmas referenced : 
bag-append_wf, 
bag_wf, 
istype-universe, 
bag-subtype-list, 
append_is_nil, 
top_wf, 
list-subtype-bag, 
istype-void, 
istype-top, 
equal_functionality_wrt_subtype_rel2, 
list_wf, 
equal-empty-bag, 
equal-wf-T-base, 
empty_bag_append_lemma
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
independent_pairFormation, 
sqequalRule, 
sqequalHypSubstitution, 
productElimination, 
thin, 
independent_pairEquality, 
axiomEquality, 
hypothesis, 
equalityIsType3, 
inhabitedIsType, 
hypothesisEquality, 
extract_by_obid, 
isectElimination, 
baseClosed, 
productIsType, 
because_Cache, 
isect_memberEquality_alt, 
isectIsTypeImplies, 
universeIsType, 
instantiate, 
universeEquality, 
applyEquality, 
dependent_functionElimination, 
independent_isectElimination, 
promote_hyp, 
lambdaEquality_alt, 
voidElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
cumulativity, 
applyLambdaEquality, 
hyp_replacement, 
voidEquality, 
isect_memberEquality
Latex:
\mforall{}[T:Type].  \mforall{}[b1,b2:bag(T)].    uiff((b1  +  b2)  =  \{\};(b1  =  \{\})  \mwedge{}  (b2  =  \{\}))
Date html generated:
2019_10_15-AM-10_59_57
Last ObjectModification:
2018_10_16-PM-05_37_36
Theory : bags
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