A method of proof which proceeds by stating a proposition and then showing that it results in a contradiction, thus demonstrating the proposition to be false. In the words of G. H. Hardy, "Reductio ad absurdum, which Euclid loved so much, is one of a mathematician's finest weapons. It is a far finer gambit than any chess gambit: a chess player may offer the sacrifice of a pawn or even a piece, but a mathematician offers the game" (Coxeter and Greitzer 1967, p. 16; Hardy 1993, p. 34).
Reductio ad Absurdum
See also
ProofExplore with Wolfram|Alpha
References
Coxeter, H. S. M. and Greitzer, S. L. Geometry Revisited. Washington, DC: Math. Assoc. Amer., p. 16, 1967.Hardy, G. H. A Mathematician's Apology, reprinted with a foreword by C. P. Snow. New York: Cambridge University Press, p. 34, 1993.Referenced on Wolfram|Alpha
Reductio ad AbsurdumCite this as:
Weisstein, Eric W. "Reductio ad Absurdum." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/ReductioadAbsurdum.html