The particular function names listed above are basic logic names. There are precedents of logic names in mathematical logic, though usually they are called logical constants. For example, the equality sign is a logic name in first-order logic with equality. Usually, logic names are present in every vocabulary and their interpretations satisfy some a priori restrictions. Accordingly, we suppose that the basic logic names appear in every vocabulary, and thus there is no need to mention them when a particular vocabulary is described.
An additional logic name is introduced in . It does not necessarily appear in every vocabulary and it is not marked static. The latter is one reason why we do not use the term ``logical constants''.