The Riemann hypothesis, explained by Jørgen Veisdal: https://www.cantorsparadise.com/the-riemann-hypothesis-explained-fa01c1f75d3f
$$\boxed{{\displaystyle \zeta (s)=0,s\notin 2{\mathbb{Z}}^{-}⟹\mathrm{\Re }(s)={\displaystyle \frac{1}{2}}}}$$