more from M Fitting/R Mendelsohn

### Single Idea 9727

#### [catalogued under 4. Formal Logic / D. Modal Logic ML / 2. Tools of Modal Logic / a. Symbols of ML]

Full Idea

For modal logic we add to the syntax of classical logic two new unary operators □ (necessarily) and ◊ (possibly).

Gist of Idea

Modal logic adds □ (necessarily) and ◊ (possibly) to classical logic

Source

M Fitting/R Mendelsohn (First-Order Modal Logic [1998], 1.3)

Book Reference

Fitting,M/Mendelsohn,R: 'First-Order Modal Logic' [Synthese 1998], p.5