Nuprl Lemma : bag-member-decidable2
∀T:Type. ∀P:T ⟶ ℙ. ∀b:bag(T). ∀x:{x:T| P[x]} .
  ((∀x,y:{x:T| P[x]} .  Dec(x = y ∈ {x:T| P[x]} )) 
⇒ (∀x:{x:T| x ↓∈ b} . ∃y:{x:T| P[x]} . (x = y ∈ T)) 
⇒ Dec(x ↓∈ b))
Proof
Definitions occuring in Statement : 
bag-member: x ↓∈ bs
, 
bag: bag(T)
, 
decidable: Dec(P)
, 
prop: ℙ
, 
so_apply: x[s]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
implies: P 
⇒ Q
, 
set: {x:A| B[x]} 
, 
function: x:A ⟶ B[x]
, 
universe: Type
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
prop: ℙ
, 
exists: ∃x:A. B[x]
, 
so_apply: x[s]
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
pi1: fst(t)
, 
uimplies: b supposing a
, 
squash: ↓T
, 
istype: istype(T)
, 
nat: ℕ
, 
false: False
, 
ge: i ≥ j 
, 
not: ¬A
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
top: Top
, 
and: P ∧ Q
, 
or: P ∨ Q
, 
empty-bag: {}
, 
cons: [a / b]
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
colength: colength(L)
, 
nil: []
, 
it: ⋅
, 
so_lambda: λ2x.t[x]
, 
sq_type: SQType(T)
, 
less_than: a < b
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
decidable: Dec(P)
, 
cons-bag: x.b
, 
bag-map': bag-map'(f;b)
, 
single-bag: {x}
, 
bag-append: as + bs
, 
append: as @ bs
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
so_apply: x[s1;s2;s3]
, 
bag-map: bag-map(f;bs)
, 
true: True
, 
uiff: uiff(P;Q)
, 
rev_uimplies: rev_uimplies(P;Q)
, 
sq_or: a ↓∨ b
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
Lemmas referenced : 
istype-universe, 
bag-member_wf, 
decidable_wf, 
equal_wf, 
subtype_rel_self, 
bag_wf, 
bag-map'_wf, 
subtype_rel_bag, 
bag_to_squash_list, 
bag-subtype, 
bag_qinc, 
list-subtype-bag, 
nat_properties, 
full-omega-unsat, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
ge_wf, 
less_than_wf, 
list-cases, 
empty-bag_wf, 
product_subtype_list, 
colength-cons-not-zero, 
colength_wf_list, 
istype-false, 
le_wf, 
list_wf, 
subtract-1-ge-0, 
subtype_base_sq, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
set_subtype_base, 
int_subtype_base, 
spread_cons_lemma, 
decidable__equal_int, 
subtract_wf, 
intformnot_wf, 
itermSubtract_wf, 
itermAdd_wf, 
int_formula_prop_not_lemma, 
int_term_value_subtract_lemma, 
int_term_value_add_lemma, 
decidable__le, 
cons-bag_wf, 
nat_wf, 
bag_map_empty_lemma, 
cons_wf, 
list_ind_cons_lemma, 
list_ind_nil_lemma, 
bag-map-append, 
single-bag_wf, 
top_wf, 
map_cons_lemma, 
map_nil_lemma, 
squash_wf, 
true_wf, 
bag-member-cons, 
exists_wf, 
subtype_rel_dep_function, 
subtype_rel_sets, 
subtype_rel-equal, 
all_wf, 
bag-subtype2, 
decidable_functionality, 
decidable__bag-member2
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
sqequalRule, 
functionIsType, 
setIsType, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
universeIsType, 
productIsType, 
inhabitedIsType, 
equalityIsType1, 
setElimination, 
rename, 
setEquality, 
applyEquality, 
instantiate, 
universeEquality, 
because_Cache, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
functionExtensionality, 
dependent_functionElimination, 
dependent_set_memberEquality_alt, 
productElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_functionElimination, 
independent_isectElimination, 
imageElimination, 
intWeakElimination, 
natural_numberEquality, 
approximateComputation, 
int_eqEquality, 
isect_memberEquality_alt, 
voidElimination, 
independent_pairFormation, 
axiomEquality, 
functionIsTypeImplies, 
unionElimination, 
promote_hyp, 
hypothesis_subsumption, 
applyLambdaEquality, 
equalityIsType4, 
baseApply, 
closedConclusion, 
baseClosed, 
intEquality, 
imageMemberEquality, 
inlFormation_alt, 
inrFormation_alt, 
hyp_replacement
Latex:
\mforall{}T:Type.  \mforall{}P:T  {}\mrightarrow{}  \mBbbP{}.  \mforall{}b:bag(T).  \mforall{}x:\{x:T|  P[x]\}  .
    ((\mforall{}x,y:\{x:T|  P[x]\}  .    Dec(x  =  y))  {}\mRightarrow{}  (\mforall{}x:\{x:T|  x  \mdownarrow{}\mmember{}  b\}  .  \mexists{}y:\{x:T|  P[x]\}  .  (x  =  y))  {}\mRightarrow{}  Dec(x  \mdownarrow{}\mmember{}  b))
Date html generated:
2019_10_16-AM-11_30_06
Last ObjectModification:
2018_10_10-PM-07_22_58
Theory : bags_2
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