Nuprl Lemma : bag-reduce_wf
∀[T:Type]. ∀[zero:T]. ∀[f:T ⟶ T ⟶ T].
  (∀[bs:bag(T)]. (bag-reduce(x,y.f[x;y];zero;bs) ∈ T)) supposing (Assoc(T;λx,y. f[x;y]) and Comm(T;λx,y. f[x;y]))
Proof
Definitions occuring in Statement : 
bag-reduce: bag-reduce(x,y.f[x; y];zero;bs), 
bag: bag(T), 
comm: Comm(T;op), 
assoc: Assoc(T;op), 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
so_apply: x[s1;s2], 
member: t ∈ T, 
lambda: λx.A[x], 
function: x:A ⟶ B[x], 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
bag: bag(T), 
quotient: x,y:A//B[x; y], 
and: P ∧ Q, 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
bag-reduce: bag-reduce(x,y.f[x; y];zero;bs), 
prop: ℙ, 
so_apply: x[s1;s2], 
assoc: Assoc(T;op), 
infix_ap: x f y, 
comm: Comm(T;op), 
so_lambda: λ2x.t[x], 
so_apply: x[s], 
squash: ↓T, 
true: True, 
top: Top, 
iff: P ⇐⇒ Q, 
rev_implies: P ⇐ Q, 
guard: {T}, 
subtype_rel: A ⊆r B, 
label: ...$L... t, 
append: as @ bs, 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
so_apply: x[s1;s2;s3]
Lemmas referenced : 
list_wf, 
permutation_wf, 
equal_wf, 
equal-wf-base, 
bag_wf, 
assoc_wf, 
comm_wf, 
permutation-invariant, 
reduce_wf, 
squash_wf, 
true_wf, 
cons_wf, 
reduce_cons_lemma, 
iff_weakening_equal, 
list_induction, 
all_wf, 
append_wf, 
nil_wf, 
list_ind_nil_lemma, 
reduce_nil_lemma, 
list_ind_cons_lemma
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
sqequalHypSubstitution, 
pointwiseFunctionalityForEquality, 
because_Cache, 
sqequalRule, 
pertypeElimination, 
productElimination, 
thin, 
equalityTransitivity, 
hypothesis, 
equalitySymmetry, 
extract_by_obid, 
isectElimination, 
cumulativity, 
hypothesisEquality, 
lambdaFormation, 
rename, 
dependent_functionElimination, 
independent_functionElimination, 
productEquality, 
axiomEquality, 
isect_memberEquality, 
lambdaEquality, 
applyEquality, 
functionExtensionality, 
functionEquality, 
universeEquality, 
addLevel, 
hyp_replacement, 
imageElimination, 
natural_numberEquality, 
imageMemberEquality, 
baseClosed, 
levelHypothesis, 
voidElimination, 
voidEquality, 
independent_isectElimination
Latex:
\mforall{}[T:Type].  \mforall{}[zero:T].  \mforall{}[f:T  {}\mrightarrow{}  T  {}\mrightarrow{}  T].
    (\mforall{}[bs:bag(T)].  (bag-reduce(x,y.f[x;y];zero;bs)  \mmember{}  T))  supposing 
          (Assoc(T;\mlambda{}x,y.  f[x;y])  and 
          Comm(T;\mlambda{}x,y.  f[x;y]))
Date html generated:
2017_10_01-AM-08_48_08
Last ObjectModification:
2017_07_26-PM-04_32_22
Theory : bags
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