7
Ordering the Types
•
An order on the FO
k
types of A is a total
preorder
a
¹
b
s.t.
a
¼
b
iff
a
¹
b
and
b
¹
a
•
•
There are many possible orders of types…
•
•
Theorem
There exists an IFP formula
f
(
x
,
y
)
that computes an order on types
•
Proof
[ in class ]