They can instead be described in the metalanguage, as equivalence classes of logical formulas.

These deterministic dependencies have the form of logical formulas connecting the items.

In a simple case, one may use logical formulae, such as in:

The names depend on what the logical formula looks like.

The database schema uses logical formulas to create integrity constraints.

These sentences are translated into a formal logical formula (according to an unambiguous, artificial language).

This is translated into the logical formula "red AND car".

All logical formulas can be converted into disjunctive normal form.

Consider some logical formula, or expression, as in our Boolean net.

Before proceeding to stage 5, the models are expressed in logical formulae.