Nuprl Lemma : combine-list-append
∀[A:Type]. ∀[f:A ⟶ A ⟶ A].
  (∀[as,bs:A List].
     combine-list(x,y.f[x;y];as @ bs) = combine-list(x,y.f[x;y];bs @ as) ∈ A supposing 0 < ||as @ bs||) supposing 
     (Comm(A;λx,y. f[x;y]) and 
     Assoc(A;λx,y. f[x;y]))
Proof
Definitions occuring in Statement : 
combine-list: combine-list(x,y.f[x; y];L), 
length: ||as||, 
append: as @ bs, 
list: T List, 
comm: Comm(T;op), 
assoc: Assoc(T;op), 
less_than: a < b, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
so_apply: x[s1;s2], 
lambda: λx.A[x], 
function: x:A ⟶ B[x], 
natural_number: $n, 
universe: Type, 
equal: s = t ∈ T
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
uimplies: b supposing a, 
all: ∀x:A. B[x], 
or: P ∨ Q, 
append: as @ bs, 
so_lambda: so_lambda(x,y,z.t[x; y; z]), 
top: Top, 
so_apply: x[s1;s2;s3], 
squash: ↓T, 
so_lambda: λ2x y.t[x; y], 
so_apply: x[s1;s2], 
cons: [a / b], 
combine-list: combine-list(x,y.f[x; y];L), 
prop: ℙ, 
so_apply: x[s], 
true: True, 
subtype_rel: A ⊆r B, 
guard: {T}, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
rev_implies: P ⇐ Q, 
implies: P ⇒ Q, 
comm: Comm(T;op), 
infix_ap: x f y
Lemmas referenced : 
list-cases, 
list_ind_nil_lemma, 
combine-list_wf, 
append_back_nil, 
product_subtype_list, 
list_ind_cons_lemma, 
length_of_cons_lemma, 
cons_wf, 
reduce_hd_cons_lemma, 
reduce_tl_cons_lemma, 
less_than_wf, 
length_wf, 
append_wf, 
comm_wf, 
assoc_wf, 
equal_wf, 
squash_wf, 
true_wf, 
iff_weakening_equal, 
list_accum_cons_lemma, 
list_accum_wf, 
list_accum_permute
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
hypothesisEquality, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesis, 
dependent_functionElimination, 
unionElimination, 
sqequalRule, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
applyEquality, 
lambdaEquality, 
imageElimination, 
because_Cache, 
independent_isectElimination, 
functionExtensionality, 
imageMemberEquality, 
baseClosed, 
promote_hyp, 
hypothesis_subsumption, 
productElimination, 
natural_numberEquality, 
cumulativity, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
universeEquality, 
independent_functionElimination, 
hyp_replacement, 
applyLambdaEquality
Latex:
\mforall{}[A:Type].  \mforall{}[f:A  {}\mrightarrow{}  A  {}\mrightarrow{}  A].
    (\mforall{}[as,bs:A  List].
          combine-list(x,y.f[x;y];as  @  bs)  =  combine-list(x,y.f[x;y];bs  @  as) 
          supposing  0  <  ||as  @  bs||)  supposing 
          (Comm(A;\mlambda{}x,y.  f[x;y])  and 
          Assoc(A;\mlambda{}x,y.  f[x;y]))
Date html generated:
2017_04_17-AM-07_38_52
Last ObjectModification:
2017_02_27-PM-04_12_50
Theory : list_1
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