Bertrand-Chebyshev theorem

From the surname of Joseph Louis François Bertrand, who conjectured the theorem, and the surname of Pafnuty Chebyshev who proved it.

Bertrand-Chebyshev theorem

1. (mathematics) the theorem that there is at least one prime number between n and 2n for every n>1, i.e.:

   ${\displaystyle \forall n\in \mathbb {N} :n>1\Rightarrow \exists p\in \mathbb {P} :n<p<2n}$