Ergodic theorems for imprecise probability kinematics.

In a standard Bayesian setting, there is often ambiguity in prior choice, as one may have not sufficient information to uniquely identify a suitable prior probability measure encapsulating initial beliefs. To overcome this, we specify a set $\mathcal{P}$ of plausible prior probability measures; as more and more data are collected, $\mathcal{P}$ is updated using Jeffrey's rule of conditioning, an alternative to Bayesian updating which proves to be more philosophically compelling in many situations. We build the sequence $(\mathcal{P}^*_k)$ of successive updates of $\mathcal{P}$ and we develop an ergodic theory for its limit, for countable and uncountable sample space $\Omega$. A result of this ergodic theory is a strong law of large numbers when $\Omega$ is uncountable. We also develop procedure for updating lower probabilities using Jeffrey's rule of conditioning.