Belief revision

crossing a road
when we cross a road, and go from one side to the next, we are changing our core belief of being on one side as opposed to another. Without any revision of rules or belief, we can be on the left side of the road, and then cross a road, thus believing we are now on the right side of it.

Assume belief set R:

person(p1).
side(s1).
side(s2).
onSide(p1, s1).
onSide(p1, s2).
crossing(p1).

Some things to consider, a person cannot be on both the left and right sides of the road at the same time.
Crossing is our transitioning period where we are neither on the left or right sides of the road.

Ax(crossing(x)^person(x) -> Ay(!onSide(x, y))).
AxEy(person(x)^onSide(x, y) -> !crossing(x)).