Information usually comes in pieces, from different sources. It refers
to different, but related questions. Therefore information needs to be
aggregated and focused onto the relevant questions. Considering
combination and focusing of information as the relevant operations leads
to a generic algebraic structure for information. This book introduces
and studies information from this algebraic point of view. Algebras of
information provide the necessary abstract framework for generic
inference procedures. They allow the application of these procedures to
a large variety of different formalisms for representing information. At
the same time they permit a generic study of conditional independence, a
property considered as fundamental for knowledge presentation.
Information algebras provide a natural framework to define and study
uncertain information. Uncertain information is represented by random
variables that naturally form information algebras. This theory also
relates to probabilistic assumption-based reasoning in information
systems and is the basis for the belief functions in the Dempster-Shafer
theory of evidence.