Editing Mathematical proof (section)

===Computer-assisted proofs===
{{Main|Computer-assisted proof }}
Until the twentieth century it was assumed that any proof could, in principle, be checked by a competent mathematician to confirm its validity.<ref name="Krantz">[http://www.math.wustl.edu/~sk/eolss.pdf The History and Concept of Mathematical Proof], Steven G. Krantz. 1. February 5, 2007</ref> However, computers are now used both to prove theorems and to carry out calculations that are too long for any human or team of humans to check; the first proof of the [[four color theorem]] is an example of a computer-assisted proof. Some mathematicians are concerned that the possibility of an error in a computer program or a run-time error in its calculations calls the validity of such computer-assisted proofs into question. In practice, the chances of an error invalidating a computer-assisted proof can be reduced by incorporating redundancy and self-checks into calculations, and by developing multiple independent approaches and programs. Errors can never be completely ruled out in case of verification of a proof by humans either, especially if the proof contains natural language and requires deep mathematical insight to uncover the potential hidden assumptions and fallacies involved.