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Unchanged Properties

Actions usually cause changes to only a relatively small portion of the world, leaving the majority of properties and relationships in the world unchanged. For instance, the action of my writing this dissertation does not affect the color of milk, the number of states in the different countries of the world or the number of hours in a day. The persistence problem [Sho88] is centered around predicting the properties that remain unchanged as actions are performed. In the context of situation calculus [MH69], McCarthy and Hayes discuss an obvious way of handling this problem using axioms that represent how the world stays the same called frame axioms and how that method leads to the frame problem - the need for a large number of frame axioms to describe each action.

Darsana Josyula 2006-01-16