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I have one doubt in the below Kripke :

What would be the result of (X_prev phi) on s0, as it is the initial state ? 

Would it be satisfied or not satisfied ?

Thanks in advance.

in * TF "Emb. Sys. and Rob." by (2.9k points)

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The question is not well posed, there are two previous operators, a weak and a strong one, written as PWX and PSX, and both can only be interpreted on paths and not on states. So you cannot ask whether it holds in a particular states. But if we consider the path s0->s1->s1... that you most probably mean, then the strong previous operator would be false in position 0, since there is no previous state and the weak previous operator would be true for the same reason. If you ask for PWX a in position 1, it will be true and also PSX a will be true there. Does this help?
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Thanks a lot for the explanation.

1. Could you please let me know the representation in Q 8 (c) : 14.02.2018 (https://es.cs.uni-kl.de/teaching/vrs/exams/2018.02.14.vrs/2018.02.14.vrs.solutions.pdf) is weak or strong ?

2. Could you please also let me know the slide number of LTL module which I can refer to for this ?
It is a weak one since there is no underline. The semantics of these operators is described on slide 13.
Thanks a lot :)
It is clear now.

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