Nuprl Lemma : bag-count-drop
∀[T:Type]
  ∀eq:EqDecider(T). ∀x:T. ∀bs:bag(T).
    ((x ↓∈ bs ∧ ((#x in bag-drop(eq;bs;x)) = ((#x in bs) - 1) ∈ ℕ))
    ∨ ((¬x ↓∈ bs) ∧ ((#x in bag-drop(eq;bs;x)) = (#x in bs) ∈ ℕ)))
Proof
Definitions occuring in Statement : 
bag-drop: bag-drop(eq;bs;a), 
bag-count: (#x in bs), 
bag-member: x ↓∈ bs, 
bag: bag(T), 
deq: EqDecider(T), 
nat: ℕ, 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
not: ¬A, 
or: P ∨ Q, 
and: P ∧ Q, 
subtract: n - m, 
natural_number: $n, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
all: ∀x:A. B[x], 
member: t ∈ T, 
or: P ∨ Q, 
exists: ∃x:A. B[x], 
and: P ∧ Q, 
cand: A c∧ B, 
sq_stable: SqStable(P), 
implies: P ⇒ Q, 
squash: ↓T, 
prop: ℙ, 
guard: {T}, 
not: ¬A, 
false: False, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
sq_or: a ↓∨ b, 
uiff: uiff(P;Q), 
uimplies: b supposing a, 
subtype_rel: A ⊆r B, 
sq_type: SQType(T), 
true: True, 
nat: ℕ, 
single-bag: {x}, 
deq: EqDecider(T), 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
eqof: eqof(d), 
ifthenelse: if b then t else f fi , 
decidable: Dec(P), 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
top: Top, 
bfalse: ff, 
bnot: ¬bb, 
assert: ↑b, 
bag-drop: bag-drop(eq;bs;a)
Lemmas referenced : 
bag-remove1-property, 
sq_stable__bag-member, 
not_wf, 
bag-member_wf, 
equal_wf, 
nat_wf, 
bag-count_wf, 
bag-drop_wf, 
bag_wf, 
deq_wf, 
bag-member-append, 
single-bag_wf, 
bag-member-single, 
subtype_base_sq, 
int_subtype_base, 
subtract_wf, 
cons_wf, 
nil_wf, 
list-subtype-bag, 
ifthenelse_wf, 
bool_wf, 
eqtt_to_assert, 
safe-assert-deq, 
decidable__equal_int, 
full-omega-unsat, 
intformnot_wf, 
intformeq_wf, 
itermSubtract_wf, 
itermAdd_wf, 
itermConstant_wf, 
itermVar_wf, 
int_formula_prop_not_lemma, 
int_formula_prop_eq_lemma, 
int_term_value_subtract_lemma, 
int_term_value_add_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_wf, 
eqff_to_assert, 
bool_cases_sqequal, 
bool_subtype_base, 
assert-bnot, 
member_wf, 
squash_wf, 
true_wf, 
bag-count-append, 
subtype_rel_self, 
iff_weakening_equal, 
add_functionality_wrt_eq, 
bag-count-single, 
unit_wf2
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
because_Cache, 
dependent_functionElimination, 
hypothesisEquality, 
unionElimination, 
inlFormation, 
productElimination, 
hypothesis, 
independent_functionElimination, 
sqequalRule, 
imageMemberEquality, 
baseClosed, 
imageElimination, 
independent_pairFormation, 
productEquality, 
inrFormation, 
cumulativity, 
voidElimination, 
universeEquality, 
hyp_replacement, 
equalitySymmetry, 
applyLambdaEquality, 
independent_isectElimination, 
instantiate, 
intEquality, 
applyEquality, 
natural_numberEquality, 
equalityTransitivity, 
lambdaEquality, 
setElimination, 
rename, 
equalityElimination, 
approximateComputation, 
dependent_pairFormation, 
int_eqEquality, 
isect_memberEquality, 
voidEquality, 
promote_hyp, 
unionEquality
Latex:
\mforall{}[T:Type]
    \mforall{}eq:EqDecider(T).  \mforall{}x:T.  \mforall{}bs:bag(T).
        ((x  \mdownarrow{}\mmember{}  bs  \mwedge{}  ((\#x  in  bag-drop(eq;bs;x))  =  ((\#x  in  bs)  -  1)))
        \mvee{}  ((\mneg{}x  \mdownarrow{}\mmember{}  bs)  \mwedge{}  ((\#x  in  bag-drop(eq;bs;x))  =  (\#x  in  bs))))
Date html generated:
2019_10_16-AM-11_31_24
Last ObjectModification:
2018_08_21-PM-01_59_33
Theory : bags_2
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