On the Use of Epistemic Ordering Functions as Decision Criteria for Automated and Assisted Belief Revision in SNePS

We implement belief revision in SNePS based on a user-supplied epistemic ordering of propositions. We provide a decision procedure that performs revision completely automatically when given a well preorder. We also provide a decision procedure for revision that, when given a total preorder, simulates a well preorder by making a minimal number of queries to the user when multiple propositions within a minimally-inconsistent set are minimally-epistemically-entrenched. The first procedure uses Op|Σ|q units of space, and completes within Op|Σ| ̈smaxq units of time, where Σ is the set of distinct minimally-inconsistent sets, and smax is the number of propositions in the largest minimally-inconsistent set. The second procedure uses Op|Σ| ̈smaxq space and Op|Σ| 2 ̈smaxq time. We demonstrate how our changes generalize previous techniques employed in SNePS.