# Definition:Semantic Equivalence/Predicate Logic/Definition 2

## Definition

Let $\mathbf A, \mathbf B$ be WFFs of predicate logic.

Then $\mathbf A$ and $\mathbf B$ are equivalent if and only if:

$\mathbf A \iff \mathbf B$ is a tautology

where $\iff$ is the biconditional connective.