Nuprl Lemma : has-value-is-list-approx-is-type
∀[T:Type]. ∀[t:colist(T)]. ∀[n:ℕ].
  ((λis-list,t. eval u = t in if u is a pair then is-list (snd(u)) otherwise if u = Ax then tt otherwise ⊥^n ⊥ t)↓ ∈ Typ\000Ce)
Proof
Definitions occuring in Statement : 
colist: colist(T), 
fun_exp: f^n, 
nat: ℕ, 
has-value: (a)↓, 
callbyvalue: callbyvalue, 
bottom: ⊥, 
btrue: tt, 
uall: ∀[x:A]. B[x], 
pi2: snd(t), 
ispair: if z is a pair then a otherwise b, 
isaxiom: if z = Ax then a otherwise b, 
member: t ∈ T, 
apply: f a, 
lambda: λx.A[x], 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
member: t ∈ T, 
nat: ℕ, 
implies: P ⇒ Q, 
false: False, 
ge: i ≥ j , 
uimplies: b supposing a, 
not: ¬A, 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
exists: ∃x:A. B[x], 
all: ∀x:A. B[x], 
top: Top, 
and: P ∧ Q, 
prop: ℙ, 
decidable: Dec(P), 
or: P ∨ Q, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
uiff: uiff(P;Q), 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
sq_type: SQType(T), 
guard: {T}, 
bnot: ¬bb, 
assert: ↑b, 
compose: f o g, 
has-value: (a)↓, 
pi2: snd(t), 
ext-eq: A ≡ B
Lemmas referenced : 
nat_properties, 
full-omega-unsat, 
intformand_wf, 
intformle_wf, 
itermConstant_wf, 
itermVar_wf, 
intformless_wf, 
istype-int, 
int_formula_prop_and_lemma, 
istype-void, 
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, 
istype-less_than, 
fun_exp0_lemma, 
strictness-apply, 
has-value_wf_base, 
subtract-1-ge-0, 
fun_exp_unroll, 
decidable__le, 
intformnot_wf, 
int_formula_prop_not_lemma, 
istype-le, 
eq_int_wf, 
eqtt_to_assert, 
assert_of_eq_int, 
intformeq_wf, 
int_formula_prop_eq_lemma, 
eqff_to_assert, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_int, 
value-type-has-value, 
colist_wf, 
colist-value-type, 
co-list-cases, 
unit_subtype_colist, 
sqle_wf_base, 
subtype_rel_transitivity, 
b-union_wf, 
unit_wf2, 
subtype_rel_b-union-right, 
colist-ext, 
istype-nat, 
istype-universe
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
introduction, 
cut, 
thin, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
sqequalRule, 
intWeakElimination, 
lambdaFormation_alt, 
natural_numberEquality, 
independent_isectElimination, 
approximateComputation, 
independent_functionElimination, 
dependent_pairFormation_alt, 
lambdaEquality_alt, 
int_eqEquality, 
dependent_functionElimination, 
isect_memberEquality_alt, 
voidElimination, 
independent_pairFormation, 
universeIsType, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
functionIsTypeImplies, 
inhabitedIsType, 
baseClosed, 
because_Cache, 
dependent_set_memberEquality_alt, 
unionElimination, 
equalityElimination, 
productElimination, 
equalityIstype, 
promote_hyp, 
instantiate, 
cumulativity, 
callbyvalueReduce, 
hypothesis_subsumption, 
productEquality, 
isectIsTypeImplies, 
universeEquality
Latex:
\mforall{}[T:Type].  \mforall{}[t:colist(T)].  \mforall{}[n:\mBbbN{}].
    ((\mlambda{}is-list,t.  eval  u  =  t  in
                                if  u  is  a  pair  then  is-list  (snd(u))  otherwise  if  u  =  Ax  then  tt  otherwise  \mbot{}\^{}n  
        \mbot{}  
        t)\mdownarrow{}  \mmember{}  Type)
 Date html generated: 
2019_10_16-AM-11_38_22
 Last ObjectModification: 
2019_06_26-PM-05_07_14
Theory : eval!all
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