  In [Fortini et al., Stoch. Proc. Appl. 100 (2002), 147--165] it is
demonstrated that a recurrent Markov exchangeable process in the sense of
Diaconis and Freedman is essentially a partially exchangeable process in the
sense of de Finetti. In case of finite sequences there is not such an
equivalence. We analyze both finite partially exchangeable and finite Markov
exchangeable binary sequences and formulate necessary and sufficient conditions
for extendibility in both cases.
