 Logical validity (source code)

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= Logical validity
{title2=$\Gamma\models A$}

An argument has <logical validity> in <classical propositional logic> when no <Boolean valuation> makes all premises $\Gamma$ true and the conclusion $A$ false: $\Gamma\models A$. With no premises, $\models A$ says that $A$ is a <tautology>. See https://forallx.openlogicproject.org/html/Ch12.html[forall x: Calgary, sections 12.4–12.6].

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