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A tautology can be indicated like so: $\models \phi$

What is the notation for an inconsistency? $\not \models \phi$?

What is the notation for a contingency?

Fabian
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1 Answers1

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Inconsistency is not $\not \vDash \phi$, because that is merely saying that $\phi$ is not a tautology, so it could still be either an inconsistency or a contingeny.

Instead, an inconsistency is: $\phi \vDash \bot$

When $\not \vDash \phi$ and $\not \vDash \neg \phi$, then $\phi$ is a contingency. I personally have not seen one symbol for this.

Bram28
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