...31#31.

One of the referees suggested that using the fluents Blocked1 and Blocked2 and the corresponding actions was too special, and we should say that the room is stuffy when all the vents are blocked. We can accommodate his preference by introducing the vents as objects and using the axiom

 32#32

and a corresponding axiom for the effect of unblocking a vent.

This is just a step towards a general commonsense theory of the effects of ventilation on stuffiness. Such a theory would have to take into account the fact that blocking the vents does not make the room stuffy under all circumstances. For now it's simpler to just consider the particular room with exactly two vents.

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...friends.

The ideas of internal and external events of the preceding sections are independent of the formalism used for nonmonotonic reasoning. For example, Golog [Rei01] or the Causal Calculator [aA01] could be used-perhaps with some modifications for the buzzer and the oscillating stuffy room.

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...situation.

Actually part of the stolen car scenario can be treated provided we don't suppose that the car being missing is to be projected from information about the past. Certainly we can go forward from the situation in which the car is missing to further events in the future. Likewise, in the story of Junior's travels [McC92], we can assert that Junior loses his ticket to Moscow in London and reason forward from that fact.

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...change

``events and change'' would be better terminology

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...89#89.

I pound the table here because of some resistance to the idea that axiomatic set theory makes logical AI easier.

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