IID Vs Exchangeability
It is shown in Vovk (1986), in the binomial case, that the IID deficiency of a data sequence ⚠ $x$
can be split into two components:
- the exchangeability deficiency of
⚠ $x$
- the randomness deficiency of the multiset of the observations in
⚠ $x$
(i.e.,⚠ $x$
with the order of its elements erased).
The problem is to extend this to general observation spaces.
Can we characterize, in a simple way, the randomness deficiency of a multiset (as in the second component above)? (In the binary case, this is done in Vovk 1986.)
Bibliography
- Vladimir Vovk (1986). On the concept of Bernoulli property. ''Russian Mathematical Surveys]], 41:247–248.