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?
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?
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.