### Single Idea 9528

#### [catalogued under 4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / b. Terminology of PL]

Full Idea

If a well-formed formula of propositional calculus takes the value T for all possible assignments of truth-values to its variables, it is said to be a 'tautology'.

Gist of Idea

A wff is a 'tautology' if all assignments to variables result in the value T

Source

E.J. Lemmon (Beginning Logic [1965], 2.3)

Book Reference

Lemmon,E.J.: 'Beginning Logic' [Nelson 1979], p.68

Related Idea

Idea 13520
A 'tautology' must include connectives **[Wolf,RS]**