  Belief revision is an operation that aims at modifying old beliefs so that
they become consistent with new ones. The issue of belief revision has been
studied in various formalisms, in particular, in qualitative algebras (QAs) in
which the result is a disjunction of belief bases that is not necessarily
representable in a QA. This motivates the study of belief revision in
formalisms extending QAs, namely, their propositional closures: in such a
closure, the result of belief revision belongs to the formalism. Moreover, this
makes it possible to define a contraction operator thanks to the Harper
identity. Belief revision in the propositional closure of QAs is studied, an
algorithm for a family of revision operators is designed, and an open-source
implementation is made freely available on the web. (This is the extended
version of an article originally presented at the 14th International Conference
on Principles of Knowledge Representation and Reasoning.)
