Nuprl Lemma : bag-count-single
∀[T:Type]. ∀[eq:EqDecider(T)]. ∀[x,y:T].  ((#x in [y]) = if eq x y then 1 else 0 fi  ∈ ℤ)
Proof
Definitions occuring in Statement : 
bag-count: (#x in bs), 
cons: [a / b], 
nil: [], 
deq: EqDecider(T), 
ifthenelse: if b then t else f fi , 
uall: ∀[x:A]. B[x], 
apply: f a, 
natural_number: $n, 
int: ℤ, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
subtype_rel: A ⊆r B, 
uimplies: b supposing a, 
bag-filter: [x∈b|p[x]], 
all: ∀x:A. B[x], 
top: Top, 
deq: EqDecider(T), 
implies: P ⇒ Q, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
uiff: uiff(P;Q), 
and: P ∧ Q, 
eqof: eqof(d), 
ifthenelse: if b then t else f fi , 
bag-size: #(bs), 
length: ||as||, 
list_ind: list_ind, 
cons: [a / b], 
nil: [], 
bfalse: ff, 
exists: ∃x:A. B[x], 
prop: ℙ, 
or: P ∨ Q, 
sq_type: SQType(T), 
guard: {T}, 
bnot: ¬bb, 
assert: ↑b, 
false: False, 
not: ¬A
Lemmas referenced : 
bag-count-sqequal, 
cons_wf, 
nil_wf, 
list-subtype-bag, 
filter_cons_lemma, 
filter_nil_lemma, 
bool_wf, 
eqtt_to_assert, 
safe-assert-deq, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
deq_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalRule, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
because_Cache, 
cumulativity, 
hypothesisEquality, 
hypothesis, 
applyEquality, 
independent_isectElimination, 
lambdaEquality, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
setElimination, 
rename, 
lambdaFormation, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
productElimination, 
natural_numberEquality, 
dependent_pairFormation, 
promote_hyp, 
instantiate, 
independent_functionElimination, 
axiomEquality, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[eq:EqDecider(T)].  \mforall{}[x,y:T].    ((\#x  in  [y])  =  if  eq  x  y  then  1  else  0  fi  )
 Date html generated: 
2018_05_21-PM-09_45_50
 Last ObjectModification: 
2017_07_26-PM-06_29_53
Theory : bags_2
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