  There are different approaches to qualitative probability, which includes
subjective probability. We developed a representation of qualitative
probability based on relational systems, which allows modeling uncertainty by
probability structures and is more coherent than existing approaches. This
setting makes it possible proving that any comparative probability is induced
by some probability structure (Theorem 2.1), that classical probability is a
probability structure (Theorem 2.2) and that inflated, i.e., larger than 1,
probability is also a probability structure (Theorem 2.3). In addition, we
study representation of probability structures by classical probability.
