2. The [[Riemann hypothesis]], which states that a certain function investigated by Bernhard Riemann in the 19th century is only equal to zero for complex numbers with real part equal to 1/2. (The so-called trivial zeroes occur at -2, -4, etc.) | 2. The [[Riemann hypothesis]], which states that a certain function investigated by Bernhard Riemann in the 19th century is only equal to zero for complex numbers with real part equal to 1/2. (The so-called trivial zeroes occur at -2, -4, etc.) |