Nuprl Lemma : mutual-corec-ext
∀[k:ℕ]. ∀[F:(ℕk ⟶ Type) ⟶ ℕk ⟶ Type].
  (mutual-corec(T.F[T]) ≡ F[mutual-corec(T.F[T])]) supposing (k-Monotone(T.F[T]) and k-Continuous(T.F[T]))
Proof
Definitions occuring in Statement : 
mutual-corec: mutual-corec(T.F[T]), 
k-continuous: k-Continuous(T.F[T]), 
k-monotone: k-Monotone(T.F[T]), 
k-ext: A ≡ B, 
int_seg: {i..j-}, 
nat: ℕ, 
uimplies: b supposing a, 
uall: ∀[x:A]. B[x], 
so_apply: x[s], 
function: x:A ⟶ B[x], 
natural_number: $n, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
uimplies: b supposing a, 
all: ∀x:A. B[x], 
member: t ∈ T, 
nat: ℕ, 
implies: P ⇒ Q, 
false: False, 
ge: i ≥ j , 
guard: {T}, 
prop: ℙ, 
k-subtype: A ⊆ B, 
subtype_rel: A ⊆r B, 
top: Top, 
so_apply: x[s], 
decidable: Dec(P), 
or: P ∨ Q, 
iff: P ⇐⇒ Q, 
and: P ∧ Q, 
not: ¬A, 
rev_implies: P ⇐ Q, 
uiff: uiff(P;Q), 
subtract: n - m, 
le: A ≤ B, 
less_than': less_than'(a;b), 
true: True, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
ifthenelse: if b then t else f fi , 
bfalse: ff, 
exists: ∃x:A. B[x], 
sq_type: SQType(T), 
bnot: ¬bb, 
assert: ↑b, 
k-monotone: k-Monotone(T.F[T]), 
nequal: a ≠ b ∈ T , 
squash: ↓T, 
k-ext: A ≡ B, 
mutual-corec: mutual-corec(T.F[T]), 
so_lambda: λ2x.t[x], 
sq_stable: SqStable(P), 
k-continuous: k-Continuous(T.F[T]), 
int_seg: {i..j-}, 
lelt: i ≤ j < k, 
k-intersection: ⋂n. X[n]
Lemmas referenced : 
nat_properties, 
less_than_transitivity1, 
less_than_irreflexivity, 
ge_wf, 
less_than_wf, 
int_seg_wf, 
primrec0_lemma, 
primrec1_lemma, 
top_wf, 
decidable__le, 
subtract_wf, 
false_wf, 
not-ge-2, 
less-iff-le, 
condition-implies-le, 
minus-one-mul, 
zero-add, 
minus-one-mul-top, 
minus-add, 
minus-minus, 
add-associates, 
add-swap, 
add-commutes, 
add_functionality_wrt_le, 
add-zero, 
le-add-cancel, 
primrec-unroll, 
eq_int_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_eq_int, 
le_antisymmetry_iff, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
subtype_base_sq, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_int, 
add-subtract-cancel, 
primrec_wf, 
not-le-2, 
not-equal-2, 
le_wf, 
k-subtype_wf, 
squash_wf, 
true_wf, 
le_weakening2, 
le_weakening, 
nat_wf, 
k-monotone_wf, 
k-continuous_wf, 
k-intersection_wf, 
sq_stable__le, 
subtype_rel-equal, 
subtype_rel_transitivity
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
cut, 
lambdaFormation, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
hypothesis, 
setElimination, 
rename, 
intWeakElimination, 
natural_numberEquality, 
independent_isectElimination, 
independent_functionElimination, 
voidElimination, 
sqequalRule, 
lambdaEquality, 
dependent_functionElimination, 
axiomEquality, 
isect_memberEquality, 
voidEquality, 
applyEquality, 
functionExtensionality, 
functionEquality, 
cumulativity, 
because_Cache, 
universeEquality, 
unionElimination, 
independent_pairFormation, 
productElimination, 
addEquality, 
intEquality, 
minusEquality, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
dependent_pairFormation, 
promote_hyp, 
instantiate, 
dependent_set_memberEquality, 
hyp_replacement, 
imageElimination, 
imageMemberEquality, 
baseClosed, 
isectEquality
Latex:
\mforall{}[k:\mBbbN{}].  \mforall{}[F:(\mBbbN{}k  {}\mrightarrow{}  Type)  {}\mrightarrow{}  \mBbbN{}k  {}\mrightarrow{}  Type].
    (mutual-corec(T.F[T])  \mequiv{}  F[mutual-corec(T.F[T])])  supposing 
          (k-Monotone(T.F[T])  and 
          k-Continuous(T.F[T]))
Date html generated:
2018_05_21-PM-00_10_42
Last ObjectModification:
2017_10_18-PM-02_44_21
Theory : co-recursion
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