Nuprl Lemma : null-bag-size
∀[T:Type]. ∀[x:bag(T)].  (bag-null(x) ~ (#(x) =z 0))
Proof
Definitions occuring in Statement : 
bag-size: #(bs)
, 
bag-null: bag-null(bs)
, 
bag: bag(T)
, 
eq_int: (i =z j)
, 
uall: ∀[x:A]. B[x]
, 
natural_number: $n
, 
universe: Type
, 
sqequal: s ~ t
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
uimplies: b supposing a
, 
sq_type: SQType(T)
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
guard: {T}
, 
subtype_rel: A ⊆r B
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
nat: ℕ
, 
bfalse: ff
, 
exists: ∃x:A. B[x]
, 
prop: ℙ
, 
or: P ∨ Q
, 
bnot: ¬bb
, 
ifthenelse: if b then t else f fi 
, 
assert: ↑b
, 
false: False
, 
decidable: Dec(P)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
not: ¬A
, 
top: Top
, 
empty-bag: {}
, 
bag-null: bag-null(bs)
, 
nequal: a ≠ b ∈ T 
Lemmas referenced : 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
bag_wf, 
eq_int_wf, 
bag-size_wf, 
eqtt_to_assert, 
assert_of_eq_int, 
nat_wf, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
assert-bnot, 
neg_assert_of_eq_int, 
bag-size-zero, 
decidable__le, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformle_wf, 
itermVar_wf, 
itermConstant_wf, 
intformeq_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_var_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_eq_lemma, 
int_formula_prop_wf, 
null_nil_lemma, 
btrue_wf, 
bag-null_wf, 
assert-bag-null, 
equal-wf-T-base, 
bfalse_wf, 
bag_size_empty_lemma
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
thin, 
instantiate, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
cumulativity, 
hypothesis, 
independent_isectElimination, 
dependent_functionElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
sqequalAxiom, 
hypothesisEquality, 
sqequalRule, 
isect_memberEquality, 
because_Cache, 
universeEquality, 
applyEquality, 
natural_numberEquality, 
lambdaFormation, 
unionElimination, 
equalityElimination, 
productElimination, 
lambdaEquality, 
setElimination, 
rename, 
dependent_pairFormation, 
promote_hyp, 
voidElimination, 
int_eqEquality, 
intEquality, 
voidEquality, 
independent_pairFormation, 
computeAll, 
baseClosed, 
hyp_replacement, 
applyLambdaEquality
Latex:
\mforall{}[T:Type].  \mforall{}[x:bag(T)].    (bag-null(x)  \msim{}  (\#(x)  =\msubz{}  0))
Date html generated:
2017_10_01-AM-08_45_56
Last ObjectModification:
2017_07_26-PM-04_31_01
Theory : bags
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