Atomic Formula

logic

Definition

Atomic Formula

An atomic formula in first-order logic is a
formula that applies a predicates to terms
or equates two terms without further logical connectives. It serves as the
basic building block from which more complex formulas are constructed.

Example:

$$\begin{array}{rl}\mathrm{Human}(x)& =\text{‘x is a human’}\\ \mathrm{Mortal}(x)& =\text{‘x is a mortal’}\\ & \\ \mathrm{Human}(socrates)& ⟹\mathrm{Mortal}(socrates)\end{array}$$