Rohit Parikh


Belief Revision and Language Splitting

DIMACS Center - Room 431
Busch Campus
Piscataway, New Jersey
March 15, 2:30 p.m.


The problem of belief revision goes back to a now classic paper due to Alchourron, Gaerdenfors and Makinson (JSL-85). The central problem is how to revise a theory T when a piece of information A inconsistent with T is received. Clearly T must be contracted to a smaller theory T' which IS consistent with A and then A added to T'. However, various proposals for defining this process have run into trouble, either by being too flexible and allowing implausible update operators or by allowing ONLY the trivial update.

We propose axioms for update operators which are consistent with the AGM axioms and which block the trivial update. The axioms are based on the notion of splitting languages. In particular we show that an agent's information can be split into various subject matters in a precise and well defined way and show how this splitting can be used to obtain a belief revision process which satisfies the AGM axioms, and is provably non-trivial.

The talk will only assume familiarity with elementary Logic.