Nuprl Lemma : bag-remove1-equal
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[as,bs:bag(T)]. ∀[a,b:T].
  uiff(bag-remove1(eq;as;a) = bag-remove1(eq;bs;b) ∈ (bag(T)?);(({a} + bs) = ({b} + as) ∈ bag(T))
  ↓∨ ((¬a ↓∈ as) ∧ (¬b ↓∈ bs)))
Proof
Definitions occuring in Statement : 
bag-remove1: bag-remove1(eq;bs;a)
, 
bag-member: x ↓∈ bs
, 
bag-append: as + bs
, 
single-bag: {x}
, 
bag: bag(T)
, 
deq: EqDecider(T)
, 
sq_or: a ↓∨ b
, 
uiff: uiff(P;Q)
, 
uall: ∀[x:A]. B[x]
, 
not: ¬A
, 
and: P ∧ Q
, 
unit: Unit
, 
union: left + right
, 
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
, 
sq_or: a ↓∨ b
, 
squash: ↓T
, 
all: ∀x:A. B[x]
, 
prop: ℙ
, 
or: P ∨ Q
, 
exists: ∃x:A. B[x]
, 
true: True
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
implies: P 
⇒ Q
, 
not: ¬A
, 
false: False
, 
rev_implies: P 
⇐ Q
, 
isl: isl(x)
, 
cand: A c∧ B
, 
deq: EqDecider(T)
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
eqof: eqof(d)
, 
ifthenelse: if b then t else f fi 
, 
outl: outl(x)
, 
assert: ↑b
, 
bfalse: ff
, 
sq_type: SQType(T)
, 
bnot: ¬bb
, 
exposed-bfalse: exposed-bfalse
Lemmas referenced : 
unit_wf2, 
bag-remove1_wf, 
sq_or_wf, 
equal_wf, 
bag_wf, 
bag-append_wf, 
single-bag_wf, 
not_wf, 
bag-member_wf, 
istype-universe, 
bag-remove1-property, 
squash_wf, 
true_wf, 
subtype_rel_self, 
iff_weakening_equal, 
istype-void, 
bag-append-assoc-comm, 
btrue_wf, 
bfalse_wf, 
btrue_neq_bfalse, 
deq_wf, 
bag-remove1-member, 
bag-remove1-append1, 
eqtt_to_assert, 
safe-assert-deq, 
outl_wf, 
assert_wf, 
isl_wf, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
assert-bnot, 
iff_weakening_uiff, 
bag-remove1-non-member, 
bag-member-append, 
bag-member-single
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
independent_pairFormation, 
sqequalRule, 
sqequalHypSubstitution, 
imageElimination, 
hypothesis, 
imageMemberEquality, 
hypothesisEquality, 
thin, 
baseClosed, 
equalityIsType1, 
unionIsType, 
inhabitedIsType, 
universeIsType, 
extract_by_obid, 
isectElimination, 
dependent_functionElimination, 
productEquality, 
productElimination, 
independent_pairEquality, 
isect_memberEquality_alt, 
because_Cache, 
equalityTransitivity, 
equalitySymmetry, 
axiomEquality, 
universeEquality, 
unionElimination, 
inlFormation_alt, 
applyEquality, 
lambdaEquality_alt, 
unionEquality, 
natural_numberEquality, 
instantiate, 
independent_isectElimination, 
independent_functionElimination, 
applyLambdaEquality, 
productIsType, 
functionIsType, 
dependent_set_memberEquality_alt, 
equalityIsType3, 
setElimination, 
rename, 
voidElimination, 
inrFormation_alt, 
lambdaFormation_alt, 
equalityElimination, 
promote_hyp, 
hyp_replacement, 
inlEquality_alt, 
dependent_pairFormation_alt, 
cumulativity
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[as,bs:bag(T)].  \mforall{}[a,b:T].
    uiff(bag-remove1(eq;as;a)  =  bag-remove1(eq;bs;b);((\{a\}  +  bs)  =  (\{b\}  +  as))
    \mdownarrow{}\mvee{}  ((\mneg{}a  \mdownarrow{}\mmember{}  as)  \mwedge{}  (\mneg{}b  \mdownarrow{}\mmember{}  bs)))
Date html generated:
2019_10_16-AM-11_31_14
Last ObjectModification:
2018_10_11-AM-10_46_07
Theory : bags_2
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