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Sentence: From every reachable state it is possible to reach a state where $p$ is true.

How do you write this sentence as a CTL formula? So far I only dealt with CTL syntax and trees but maybe it will also be asked in a test how you convert a sentence to a CTL formula..

So I've read that $AX$ means all next.

Then $AXp$ should mean in all next states $p$ is true.

Now I only need the first part of the sentence: From every reachable state it is possible to reach

But how would this be expressed and how do you connect it with the $AXp$ I got?

I hope you can help me because on the internet I couldn't find some example like that? : /

tenepolis
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1 Answers1

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You can learn a lot about CTL at Wikipedia page.

The sentence you need to write, expressed more closely in the vocabulary of CTL operators, would be
Along all paths starting from current state, it always has to hold that there exists at least one path where $p$ eventually is true.

I think you can take it from there, but comment if you have troubles.

hint: The operators you will need to use are $F$, $A$, $E$ and $G$.

Sandro Lovnički
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