Nuprl Lemma : tree-ext
∀[E:Type]. tree(E) ≡ lbl:Atom × if lbl =a "leaf" then E if lbl =a "node" then left:tree(E) × tree(E) else Void fi 
Proof
Definitions occuring in Statement : 
tree: tree(E)
, 
ifthenelse: if b then t else f fi 
, 
eq_atom: x =a y
, 
ext-eq: A ≡ B
, 
uall: ∀[x:A]. B[x]
, 
product: x:A × B[x]
, 
token: "$token"
, 
atom: Atom
, 
void: Void
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
ext-eq: A ≡ B
, 
and: P ∧ Q
, 
subtype_rel: A ⊆r B
, 
member: t ∈ T
, 
tree: tree(E)
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
btrue: tt
, 
uiff: uiff(P;Q)
, 
uimplies: b supposing a
, 
ifthenelse: if b then t else f fi 
, 
sq_type: SQType(T)
, 
guard: {T}
, 
eq_atom: x =a y
, 
bfalse: ff
, 
exists: ∃x:A. B[x]
, 
prop: ℙ
, 
or: P ∨ Q
, 
bnot: ¬bb
, 
assert: ↑b
, 
false: False
, 
treeco_size: treeco_size(p)
, 
nat: ℕ
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
has-value: (a)↓
, 
tree_size: tree_size(p)
, 
le: A ≤ B
, 
less_than': less_than'(a;b)
, 
not: ¬A
Lemmas referenced : 
treeco-ext, 
eq_atom_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_eq_atom, 
subtype_base_sq, 
atom_subtype_base, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_atom, 
int_subtype_base, 
treeco_size_wf, 
subtype_partial_sqtype_base, 
nat_wf, 
set_subtype_base, 
le_wf, 
base_wf, 
value-type-has-value, 
int-value-type, 
has-value_wf-partial, 
set-value-type, 
tree_wf, 
ifthenelse_wf, 
treeco_wf, 
add-nat, 
false_wf, 
tree_size_wf, 
nat_properties
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
independent_pairFormation, 
lambdaEquality, 
sqequalHypSubstitution, 
setElimination, 
thin, 
rename, 
cut, 
introduction, 
extract_by_obid, 
hypothesis, 
isectElimination, 
hypothesisEquality, 
promote_hyp, 
productElimination, 
hypothesis_subsumption, 
applyEquality, 
sqequalRule, 
dependent_pairEquality, 
tokenEquality, 
lambdaFormation, 
unionElimination, 
equalityElimination, 
equalityTransitivity, 
equalitySymmetry, 
independent_isectElimination, 
because_Cache, 
instantiate, 
cumulativity, 
atomEquality, 
dependent_functionElimination, 
independent_functionElimination, 
dependent_pairFormation, 
voidElimination, 
dependent_set_memberEquality, 
natural_numberEquality, 
intEquality, 
baseApply, 
closedConclusion, 
baseClosed, 
callbyvalueAdd, 
universeEquality, 
productEquality, 
voidEquality, 
sqleReflexivity
Latex:
\mforall{}[E:Type]
    tree(E)  \mequiv{}  lbl:Atom  \mtimes{}  if  lbl  =a  "leaf"  then  E
                                              if  lbl  =a  "node"  then  left:tree(E)  \mtimes{}  tree(E)
                                              else  Void
                                              fi 
Date html generated:
2017_10_01-AM-08_30_25
Last ObjectModification:
2017_07_26-PM-04_24_33
Theory : tree_1
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