Revising preferences and choices

Preferences and choices are subject to be modified when new information is brought to the knowledge of an agent, such strategy may suddenly appear more reliable than such other, such restaurant has to be retrieved from the list of the ten best tables of the town. We propose here an easy way to perform this revision through a simple modification of the chain of subsets attached to the agent's behavior: it can be shown indeed that, in the rational case, these chains offer an adequate representation of preferences and of choice functions. Thus the revision problem boils down to adding, retracting or modifying some of the links of the original chain, a perspective that enables an effective treatment of the problem of iterated revision.