Source : Free On-Line Dictionary of Computing

belief revision
     
         The area of {theory change} in which
        preservation of the information in the theory to be changed
        plays a key role.
     
        A fundamental issue in belief revision is how to decide what
        information to retract in order to maintain consistency, when
        the addition of a new belief to a theory would make it
        inconsistent.  Usually, an ordering on the sentences of the
        theory is used to determine priorities among sentences, so
        that those with lower priority can be retracted.  This
        ordering can be difficult to generate and maintain.
     
        The postulates of the {AGM Theory for Belief Revision}
        describe minimal properties a revision process should have.
     
        [Better definition?]
     
        (1995-03-20)