PROPOSITIONAL CALCULUS LANGUAGE

The of a propositional calculus is defined in terms of:

a set of primitive symbols, called atomic formulas, atomic sentences, atoms, placeholders, prime formulas, proposition letters, sentence letters, or variables, and

a set of operator symbols, called connectives, logical connectives , logical operators, truth-functional connectives, truth-functors, or propositional connectives.

A well-formed formula is any atomic formula, or any formula that can built from atomic formulas by means of operator symbols according to the rules of the grammar. The , then, is defined either as being identical to its set of well-formed formulas, or as containing that set (together with, for instance, its set of connectives and variables).