Definition:Atomic WFF of Predicate Logic

Definition
An atomic WFF of predicate calculus is a WFF not containing any connectives or quantifiers.

In the Backus-Naur formal grammar for PredCalc, the atomic WFFs are precisely those WFFs fitting the metasymbol .

In the bottom-up formal grammar for PredCalc, the atomic WFFs are precisely those WFFs which can be formed by only applying the rules $\mathcal P_0, \mathcal P_n$ and $\mathcal F_n$.