Nuprl Lemma : list_ind-as-fix
∀[L:Top List]. ∀[x,F:Top].
  (rec-case(L) of
   [] => x
   b::bs =>
    r.F[r;b;bs] ~ fix((λR,L. if null(L) then x else F (R tl(L)) hd(L) tl(L) fi )) L)
Proof
Definitions occuring in Statement : 
hd: hd(l)
, 
null: null(as)
, 
tl: tl(l)
, 
list_ind: list_ind, 
list: T List
, 
ifthenelse: if b then t else f fi 
, 
uall: ∀[x:A]. B[x]
, 
top: Top
, 
so_apply: x[s1;s2;s3]
, 
apply: f a
, 
fix: fix(F)
, 
lambda: λx.A[x]
, 
sqequal: s ~ t
Definitions unfolded in proof : 
so_apply: x[s1;s2;s3]
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
all: ∀x:A. B[x]
, 
nat: ℕ
, 
implies: P 
⇒ Q
, 
false: False
, 
ge: i ≥ j 
, 
uimplies: b supposing a
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
exists: ∃x:A. B[x]
, 
not: ¬A
, 
top: Top
, 
and: P ∧ Q
, 
prop: ℙ
, 
subtype_rel: A ⊆r B
, 
guard: {T}
, 
or: P ∨ Q
, 
so_lambda: so_lambda(x,y,z.t[x; y; z])
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
cons: [a / b]
, 
colength: colength(L)
, 
so_lambda: λ2x y.t[x; y]
, 
so_apply: x[s1;s2]
, 
decidable: Dec(P)
, 
nil: []
, 
it: ⋅
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
sq_type: SQType(T)
, 
less_than: a < b
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
bfalse: ff
Lemmas referenced : 
nat_properties, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_less_lemma, 
int_formula_prop_wf, 
ge_wf, 
less_than_wf, 
top_wf, 
equal-wf-T-base, 
nat_wf, 
colength_wf_list, 
less_than_transitivity1, 
less_than_irreflexivity, 
list_wf, 
list-cases, 
list_ind_nil_lemma, 
null_nil_lemma, 
reduce_tl_nil_lemma, 
product_subtype_list, 
spread_cons_lemma, 
intformeq_wf, 
itermAdd_wf, 
int_formula_prop_eq_lemma, 
int_term_value_add_lemma, 
decidable__le, 
intformnot_wf, 
int_formula_prop_not_lemma, 
le_wf, 
equal_wf, 
subtract_wf, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
subtype_base_sq, 
set_subtype_base, 
int_subtype_base, 
decidable__equal_int, 
list_ind_cons_lemma, 
null_cons_lemma, 
reduce_tl_cons_lemma, 
reduce_hd_cons_lemma
Rules used in proof : 
sqequalSubstitution, 
sqequalRule, 
sqequalReflexivity, 
sqequalTransitivity, 
computationStep, 
isect_memberFormation, 
introduction, 
cut, 
thin, 
lambdaFormation, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
natural_numberEquality, 
independent_isectElimination, 
dependent_pairFormation, 
lambdaEquality, 
int_eqEquality, 
intEquality, 
dependent_functionElimination, 
isect_memberEquality, 
voidElimination, 
voidEquality, 
independent_pairFormation, 
computeAll, 
independent_functionElimination, 
sqequalAxiom, 
applyEquality, 
because_Cache, 
unionElimination, 
promote_hyp, 
hypothesis_subsumption, 
productElimination, 
equalityTransitivity, 
equalitySymmetry, 
applyLambdaEquality, 
dependent_set_memberEquality, 
addEquality, 
baseClosed, 
instantiate, 
cumulativity, 
imageElimination
Latex:
\mforall{}[L:Top  List].  \mforall{}[x,F:Top].
    (rec-case(L)  of
      []  =>  x
      b::bs  =>
        r.F[r;b;bs]  \msim{}  fix((\mlambda{}R,L.  if  null(L)  then  x  else  F  (R  tl(L))  hd(L)  tl(L)  fi  ))  L)
Date html generated:
2017_10_01-AM-09_10_59
Last ObjectModification:
2017_07_26-PM-04_47_13
Theory : general
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