# counterexample

A counterexample is an example which is used to prove that a statement is false.

For instance, to disprove that the statement “For all $n$, $2^{2^{n}}+1$ is prime.”, one could exhibit $5$ as a counterexample; since $2^{2^{5}}+1=641\times 6700417$, the statement is false.

Title counterexample Counterexample 2013-03-22 14:43:00 2013-03-22 14:43:00 rspuzio (6075) rspuzio (6075) 5 rspuzio (6075) Definition msc 00A20