Nuprl Lemma : bag-append-is-empty
∀[T:Type]. ∀as,bs:bag(T).  uiff((as + bs) = {} ∈ bag(T);(as = {} ∈ bag(T)) ∧ (bs = {} ∈ 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], 
all: ∀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, 
all: ∀x:A. B[x], 
uiff: uiff(P;Q), 
and: P ∧ Q, 
uimplies: b supposing a, 
squash: ↓T, 
true: True, 
subtype_rel: A ⊆r B, 
top: Top, 
bag-size: #(bs), 
exists: ∃x:A. B[x], 
prop: ℙ, 
nat: ℕ, 
or: P ∨ Q, 
empty-bag: {}, 
cons: [a / b], 
ge: i ≥ j , 
le: A ≤ B, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
false: False, 
implies: P ⇒ Q, 
not: ¬A
Lemmas referenced : 
bag-size_wf, 
bag_size_empty_lemma, 
bag-size-append, 
bag_to_squash_list, 
equal-wf-T-base, 
nat_wf, 
bag_wf, 
bag-append_wf, 
list-subtype-bag, 
empty_bag_append_lemma, 
list-cases, 
empty-bag_wf, 
product_subtype_list, 
length_of_cons_lemma, 
non_neg_length, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformeq_wf, 
itermAdd_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_eq_lemma, 
int_term_value_add_lemma, 
int_formula_prop_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
lambdaFormation, 
independent_pairFormation, 
applyEquality, 
thin, 
lambdaEquality, 
sqequalHypSubstitution, 
imageElimination, 
extract_by_obid, 
isectElimination, 
because_Cache, 
hypothesis, 
natural_numberEquality, 
sqequalRule, 
imageMemberEquality, 
hypothesisEquality, 
baseClosed, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
productElimination, 
promote_hyp, 
equalitySymmetry, 
hyp_replacement, 
Error :applyLambdaEquality, 
intEquality, 
addEquality, 
cumulativity, 
setElimination, 
rename, 
independent_isectElimination, 
independent_pairEquality, 
axiomEquality, 
dependent_functionElimination, 
equalityTransitivity, 
productEquality, 
universeEquality, 
unionElimination, 
hypothesis_subsumption, 
dependent_pairFormation, 
int_eqEquality, 
computeAll
Latex:
\mforall{}[T:Type].  \mforall{}as,bs:bag(T).    uiff((as  +  bs)  =  \{\};(as  =  \{\})  \mwedge{}  (bs  =  \{\}))
Date html generated:
2016_10_25-AM-10_23_20
Last ObjectModification:
2016_07_12-AM-06_40_10
Theory : bags
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