Nuprl Lemma : combine-list-cons
∀[A:Type]. ∀[f:A ⟶ A ⟶ A].
  ∀[L:A List]. ∀[a:A]. (combine-list(x,y.f[x;y];[a / L]) = f[a;combine-list(x,y.f[x;y];L)] ∈ A) supposing 0 < ||L|| 
  supposing Assoc(A;λx,y. f[x;y])
Proof
Definitions occuring in Statement : 
combine-list: combine-list(x,y.f[x; y];L)
, 
length: ||as||
, 
cons: [a / b]
, 
list: T List
, 
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
, 
less_than: a < b
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
false: False
, 
and: P ∧ Q
, 
cons: [a / b]
, 
top: Top
, 
combine-list: combine-list(x,y.f[x; y];L)
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
prop: ℙ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
implies: P 
⇒ Q
, 
true: True
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
assoc: Assoc(T;op)
, 
infix_ap: x f y
Lemmas referenced : 
list-cases, 
length_of_nil_lemma, 
product_subtype_list, 
length_of_cons_lemma, 
reduce_hd_cons_lemma, 
reduce_tl_cons_lemma, 
list_accum_cons_lemma, 
less_than_wf, 
length_wf, 
list_wf, 
assoc_wf, 
list_induction, 
all_wf, 
equal_wf, 
list_accum_wf, 
list_accum_nil_lemma, 
squash_wf, 
true_wf, 
iff_weakening_equal
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
introduction, 
cut, 
hypothesisEquality, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesis, 
dependent_functionElimination, 
unionElimination, 
sqequalRule, 
imageElimination, 
productElimination, 
voidElimination, 
promote_hyp, 
hypothesis_subsumption, 
isect_memberEquality, 
voidEquality, 
axiomEquality, 
because_Cache, 
natural_numberEquality, 
cumulativity, 
equalityTransitivity, 
equalitySymmetry, 
lambdaEquality, 
applyEquality, 
functionExtensionality, 
functionEquality, 
universeEquality, 
independent_functionElimination, 
lambdaFormation, 
rename, 
imageMemberEquality, 
baseClosed, 
independent_isectElimination, 
hyp_replacement, 
applyLambdaEquality
Latex:
\mforall{}[A:Type].  \mforall{}[f:A  {}\mrightarrow{}  A  {}\mrightarrow{}  A].
    \mforall{}[L:A  List]
        \mforall{}[a:A].  (combine-list(x,y.f[x;y];[a  /  L])  =  f[a;combine-list(x,y.f[x;y];L)]) 
        supposing  0  <  ||L|| 
    supposing  Assoc(A;\mlambda{}x,y.  f[x;y])
Date html generated:
2017_04_14-AM-08_41_36
Last ObjectModification:
2017_02_27-PM-03_31_29
Theory : list_0
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