Single Idea 9402

[catalogued under 4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / c. Derivation rules of PL]

Full Idea

Reduction ad Absurdum (RAA): Given a proof of B∧B from A as assumption, we may derive A as conclusion, depending on the remaining assumptions (if any).

Clarification

is 'not'

Gist of Idea

RAA: If assuming A will prove B∧B, then derive A

Source

E.J. Lemmon (Beginning Logic [1965], 1.5)

Book Reference

Lemmon,E.J.: 'Beginning Logic' [Nelson 1979], p.40